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https://arxiv.org/abs/0912.1436
On the number of zeros of multiplicity r
Let S be a finite subset of a field. For multivariate polynomials the generalized Schwartz-Zippel bound [2], [4] estimates the number of zeros over Sx...xS counted with multiplicity. It does this in terms of the total degree, the number of variables and |S|. In the present work we take into account what is the leading ...
\section{Introduction}\label{secintro} In this paper we consider multivariate polynomials over an arbitrary field ${\mathbf{F}}$. Our studies focus on the zeros of given prescribed multiplicity, a concept to be defined more formally below. The definition of multiplicity that we will use relies on the Hasse derivative...
{ "timestamp": "2009-12-21T16:13:22", "yymm": "0912", "arxiv_id": "0912.1436", "language": "en", "url": "https://arxiv.org/abs/0912.1436", "abstract": "Let S be a finite subset of a field. For multivariate polynomials the generalized Schwartz-Zippel bound [2], [4] estimates the number of zeros over Sx...xS ...
https://arxiv.org/abs/1603.07261
A characterization theorem and its applications for d-orthogonality of Sheffer polynomial sets
The purpose of this paper is to find the characterization of the Sheffer polynomial sets satisfying the d-orthogonality conditions. The generating function form of these polynomial sets is given in Theorem 2.2. As applications of the Theorem 2.2, we revisit the d-orthogonal polynomial sets exist in the literature and d...
\section{Introduction} Recently, the generalization of orthogonal polynomials called "$d -orthogonal polynomials" have attracted so much attention from many authors. The well-known properties of orthogonal polynomials such as recurrence relations, Favard theorem, generating function relations and differential equat...
{ "timestamp": "2016-03-24T01:11:17", "yymm": "1603", "arxiv_id": "1603.07261", "language": "en", "url": "https://arxiv.org/abs/1603.07261", "abstract": "The purpose of this paper is to find the characterization of the Sheffer polynomial sets satisfying the d-orthogonality conditions. The generating functio...
https://arxiv.org/abs/2003.08083
Additive Representations of Natural Numbers
Every natural number greater than two may be written as the sum of a prime and a square-free number. We establish several generalisations of this, by placing divisibility conditions on the square-free number.
\section{Introduction} In 1742, Goldbach conjectured that every even integer greater than two is the sum of two primes. In 1966, Chen \cite{Chen66,Chen78} proved that every sufficiently large even integer is the sum of one prime and a product of at most two primes\footnote{Yamada \cite{Yamada2015} has shown that Chen'...
{ "timestamp": "2020-11-12T02:08:47", "yymm": "2003", "arxiv_id": "2003.08083", "language": "en", "url": "https://arxiv.org/abs/2003.08083", "abstract": "Every natural number greater than two may be written as the sum of a prime and a square-free number. We establish several generalisations of this, by plac...
https://arxiv.org/abs/1701.08504
A generalization of the practical numbers
A positive integer $n$ is practical if every $m \leq n$ can be written as a sum of distinct divisors of $n$. One can generalize the concept of practical numbers by applying an arithmetic function $f$ to each of the divisors of $n$ and asking whether all integers in a given interval can be expressed as sums of $f(d)$'s,...
\section{Introduction} Srinivasan first introduced the practical numbers as integers $n$ for which every number between $1$ and $n$ is representable as a sum of distinct divisors of $n$. In her Ph.D. thesis, the second author adapted this concept to study the degrees of divisors of $x^n-1$. Recall that $x^n - 1 = \prod...
{ "timestamp": "2017-03-24T01:02:13", "yymm": "1701", "arxiv_id": "1701.08504", "language": "en", "url": "https://arxiv.org/abs/1701.08504", "abstract": "A positive integer $n$ is practical if every $m \\leq n$ can be written as a sum of distinct divisors of $n$. One can generalize the concept of practical ...
https://arxiv.org/abs/1506.08869
Carries and the arithmetic progression structure of sets
If we want to represent integers in base $m$, we need a set $A$ of digits, which needs to be a complete set of residues modulo $m$. When adding two integers with last digits $a_1, a_2 \in A$, we find the unique $a \in A$ such that $a_1 + a_2 \equiv a$ mod $m$, and call $(a_1 + a_2 -a)/m$ the carry. Carries occur also w...
\section{Introduction} If we want to represent integers in base $m$, we need a set $A$ of digits, which needs to be a complete set of residues modulo $m$. The most popular choices are the integers in $[0, m-1]$ and the integers in $(-m/2, m/2]$. When adding two integers with last digits $a_1, a_2 \in A$, w...
{ "timestamp": "2015-07-01T02:01:33", "yymm": "1506", "arxiv_id": "1506.08869", "language": "en", "url": "https://arxiv.org/abs/1506.08869", "abstract": "If we want to represent integers in base $m$, we need a set $A$ of digits, which needs to be a complete set of residues modulo $m$. When adding two intege...
https://arxiv.org/abs/1602.08698
Equal Sums of Like Powers with Minimum Number of Terms
This paper is concerned with the diophantine system, $\sum_{i=1}^{s_1} x_i^r=\sum_{i=1}^{s_2} y_i^r,\, r=1,\,2,\,\ldots,\,k, $ where $s_1$ and $s_2$ are integers such that the total number of terms on both sides, that is, $s_1+s_2,$ is as small as possible. We define $\beta(k)$ to be the minimum value of $s_1+s_2$ for ...
\section{Introduction} \hspace*{0.25in}The Tarry-Escott problem of degree $k$ consists of finding two distinct sets of integers $\{x_1,\,x_2,\,\ldots,\,x_s\}$ and $\{y_1,\,y_2,\,\ldots,\,y_s\}$ such that \begin{equation} \sum_{i=1}^s x_i^r=\sum_{i=1}^s y_i^r,\quad r=1,\,2,\,\ldots,\,k. \label{tepsk} \end{equat...
{ "timestamp": "2016-03-01T02:11:04", "yymm": "1602", "arxiv_id": "1602.08698", "language": "en", "url": "https://arxiv.org/abs/1602.08698", "abstract": "This paper is concerned with the diophantine system, $\\sum_{i=1}^{s_1} x_i^r=\\sum_{i=1}^{s_2} y_i^r,\\, r=1,\\,2,\\,\\ldots,\\,k, $ where $s_1$ and $s_2...
https://arxiv.org/abs/2204.05250
Revisiting and improving upper bounds for identifying codes
An identifying code $C$ of a graph $G$ is a dominating set of $G$ such that any two distinct vertices of $G$ have distinct closed neighbourhoods within $C$. These codes have been widely studied for over two decades. We give an improvement over all the best known upper bounds, some of which have stood for over 20 years,...
\section{Introduction} An identifying code of a graph is a subset of its vertices that allows to distinguish all pairs of vertices by means of their neighbourhoods within the identifying code. This concept is related to other similar notions that deal with domination-based identification of the vertices/edges of a gra...
{ "timestamp": "2022-04-12T02:47:25", "yymm": "2204", "arxiv_id": "2204.05250", "language": "en", "url": "https://arxiv.org/abs/2204.05250", "abstract": "An identifying code $C$ of a graph $G$ is a dominating set of $G$ such that any two distinct vertices of $G$ have distinct closed neighbourhoods within $C...
https://arxiv.org/abs/1606.01443
Filters in the partition lattice
Given a filter $\Delta$ in the poset of compositions of $n$, we form the filter $\Pi^{*}_{\Delta}$ in the partition lattice. We determine all the reduced homology groups of the order complex of $\Pi^{*}_{\Delta}$ as ${\mathfrak S}_{n-1}$-modules in terms of the reduced homology groups of the simplicial complex $\Delta$...
\section{Introduction} \label{section_introduction} In his physics dissertation Sylvester~\cite{Sylvester} considered the even partition lattice, that is, the poset of all set partitions where the blocks have even size. He computed the M\"obius function of this lattice and showed that it equals, up to a sign, the tan...
{ "timestamp": "2016-06-07T02:08:30", "yymm": "1606", "arxiv_id": "1606.01443", "language": "en", "url": "https://arxiv.org/abs/1606.01443", "abstract": "Given a filter $\\Delta$ in the poset of compositions of $n$, we form the filter $\\Pi^{*}_{\\Delta}$ in the partition lattice. We determine all the reduc...
https://arxiv.org/abs/1712.09488
Positive Solutions of p-th Yamabe Type Equations on Infinite Graphs
Let $G=(V,E)$ be a connected infinite and locally finite weighted graph, $\Delta_p$ be the $p$-th discrete graph Laplacian. In this paper, we consider the $p$-th Yamabe type equation $$-\Delta_pu+h|u|^{p-2}u=gu^{\alpha-1}$$ on $G$, where $h$ and $g$ are known, $2<\alpha\leq p$. The prototype of this equation comes from...
\section{Introduction} Recently, the investigations of discrete weighted Laplacians and various equations on graphs have attracted much attention (cf. \cite{GLY,GLY2,GLY3,Ge1,Ge2,Ge3,Ge4,ZL}). Grigor'yan, Lin and Yang \cite{GLY3} first studied a Yamabe type equation on a finite graph $G$ as follows \begin{equa...
{ "timestamp": "2018-01-17T02:05:06", "yymm": "1712", "arxiv_id": "1712.09488", "language": "en", "url": "https://arxiv.org/abs/1712.09488", "abstract": "Let $G=(V,E)$ be a connected infinite and locally finite weighted graph, $\\Delta_p$ be the $p$-th discrete graph Laplacian. In this paper, we consider th...
https://arxiv.org/abs/2210.11270
Factorisation in the semiring of finite dynamical systems
Finite dynamical systems (FDSs) are commonly used to model systems with a finite number of states that evolve deterministically and at discrete time steps. Considered up to isomorphism, those correspond to functional graphs. As such, FDSs have a sum and product operation, which correspond to the direct sum and direct p...
\section{Introduction} Finite dynamical systems are commonly used to model systems with a finite number of states that evolve deterministically and at discrete time steps. Multiple models have been proposed for various settings, such as Boolean networks \cite{BoolNets, Goles90}, reaction systems \cite{ReactionSyste...
{ "timestamp": "2022-10-21T02:14:29", "yymm": "2210", "arxiv_id": "2210.11270", "language": "en", "url": "https://arxiv.org/abs/2210.11270", "abstract": "Finite dynamical systems (FDSs) are commonly used to model systems with a finite number of states that evolve deterministically and at discrete time steps...
https://arxiv.org/abs/2009.11069
Towards accelerated rates for distributed optimization over time-varying networks
We study the problem of decentralized optimization over time-varying networks with strongly convex smooth cost functions. In our approach, nodes run a multi-step gossip procedure after making each gradient update, thus ensuring approximate consensus at each iteration, while the outer loop is based on accelerated Nester...
\section{Introduction} In this work, we study a sum-type minimization problem \begin{align}\label{eq:initial_problem} f(x) = \frac{1}{n}\sum_{i=1}^n f_i(x) \to \min_{x\in\mathbb{R}^d}. \end{align} Convex functions $f_i$ are stored separately by nodes in communication network, which is represented by an undirec...
{ "timestamp": "2022-04-21T02:04:37", "yymm": "2009", "arxiv_id": "2009.11069", "language": "en", "url": "https://arxiv.org/abs/2009.11069", "abstract": "We study the problem of decentralized optimization over time-varying networks with strongly convex smooth cost functions. In our approach, nodes run a mul...
https://arxiv.org/abs/1603.04637
On the Randomization of Frolov's Algorithm for Multivariate Integration
We are concerned with the numerical integration of functions from the Sobolev space $H^{r,\text{mix}}([0,1]^d)$ of dominating mixed smoothness $r\in\mathbb{N}$ over the $d$-dimensional unit cube.In 1976, K. K. Frolov introduced a deterministic quadrature rule whose worst case error has the order $n^{-r} \, (\log n)^{(d...
\section{Introduction} Many applications deal with multivariate functions $f$ which are smooth in the sense that certain weak derivatives $\diff^\alpha f$ exist and are square-integrable, functions from a \textit{Sobolev space}. Which derivatives $\diff^\alpha f$ of $f$ are known to be existent and square-integrable ...
{ "timestamp": "2016-03-17T01:09:50", "yymm": "1603", "arxiv_id": "1603.04637", "language": "en", "url": "https://arxiv.org/abs/1603.04637", "abstract": "We are concerned with the numerical integration of functions from the Sobolev space $H^{r,\\text{mix}}([0,1]^d)$ of dominating mixed smoothness $r\\in\\ma...
https://arxiv.org/abs/2110.08492
Asymmetric coloring of locally finite graphs and profinite permutation groups: Tucker's Conjecture confirmed
An asymmetric coloring of a graph is a coloring of its vertices that is not preserved by any non-identity automorphism of the graph. The motion of a graph is the minimal degree of its automorphism group, i.e., the minimum number of elements displaced by any non-identity automorphism. In this paper we confirm Tom Tucker...
\section{Introduction} A graph is \emph{locally finite} if every vertex has finite degree. A graph is \emph{asymmetric} if it has no nontrivial automorphisms. A \emph{coloring} of the vertices of a graph is asymmetric if no non-identity automorphisms of the graph preserves the coloring. This author established in 197...
{ "timestamp": "2021-11-16T02:11:31", "yymm": "2110", "arxiv_id": "2110.08492", "language": "en", "url": "https://arxiv.org/abs/2110.08492", "abstract": "An asymmetric coloring of a graph is a coloring of its vertices that is not preserved by any non-identity automorphism of the graph. The motion of a graph...
https://arxiv.org/abs/1912.02225
Intrinsic Topological Transforms via the Distance Kernel Embedding
Topological transforms are parametrized families of topological invariants, which, by analogy with transforms in signal processing, are much more discriminative than single measurements. The first two topological transforms to be defined were the Persistent Homology Transform and Euler Characteristic Transform, both of...
\section{Introduction} \input{intro} \section{The Distance Kernel} \label{sec:distkernel} \input{distkernel} \section{The Distance Kernel Embedding} \label{sec:distkernelembed} \input{distkernelembed} \section{Finite Approximation of the Distance Kernel Embedding} \label{sec:discretization} \input{dis...
{ "timestamp": "2020-04-01T02:03:23", "yymm": "1912", "arxiv_id": "1912.02225", "language": "en", "url": "https://arxiv.org/abs/1912.02225", "abstract": "Topological transforms are parametrized families of topological invariants, which, by analogy with transforms in signal processing, are much more discrimi...
https://arxiv.org/abs/1809.08554
An explicit solution for a multimarginal mass transportation problem
We construct an explicit solution for the multimarginal transportation problem on the unit cube $[0,1]^3$ with the cost function $xyz$ and one-dimensional uniform projections. We show that the primal problem is concentrated on a set with non-constant local dimension and admits many solutions, whereas the solution to th...
\section{Introduction} \subsection{Notation} Assume we are given $n$ polish spaces $X_1$, $X_2$, \dots, $X_n$, equipped with probability measures $\mu_i$ on $X_i$ and a cost function $c: X_1 \times \dots \times X_n \to \mathbb{R}$. In multimarginal Monge-Kantorovich problem (called primal problem throughout this pape...
{ "timestamp": "2020-02-25T02:10:29", "yymm": "1809", "arxiv_id": "1809.08554", "language": "en", "url": "https://arxiv.org/abs/1809.08554", "abstract": "We construct an explicit solution for the multimarginal transportation problem on the unit cube $[0,1]^3$ with the cost function $xyz$ and one-dimensional...
https://arxiv.org/abs/1607.00854
Lecture Notes on the ARV Algorithm for Sparsest Cut
One of the landmarks in approximation algorithms is the $O(\sqrt{\log n})$-approximation algorithm for the Uniform Sparsest Cut problem by Arora, Rao and Vazirani from 2004. The algorithm is based on a semidefinite program that finds an embedding of the nodes respecting the triangle inequality. Their core argument show...
\section{Introduction} Let $G = (V,E)$ be a complete, undirected graph on $|V| = n$ nodes and let $c : E \to \setR_{\geq 0}$ be a cost function on the edges. For a subset $S \subseteq V$ of nodes, let $\delta(S) := \{ \{ i,j\} \in E \mid |\{ i,j\} \cap S| = 1\}$ be the induced \emph{cut}. We abbreviate $c(\delta(S)) :...
{ "timestamp": "2016-07-05T02:13:18", "yymm": "1607", "arxiv_id": "1607.00854", "language": "en", "url": "https://arxiv.org/abs/1607.00854", "abstract": "One of the landmarks in approximation algorithms is the $O(\\sqrt{\\log n})$-approximation algorithm for the Uniform Sparsest Cut problem by Arora, Rao an...
https://arxiv.org/abs/2012.07221
Intersecting longest paths in chordal graphs
We consider the size of the smallest set of vertices required to intersect every longest path in a chordal graph. Such sets are known as longest path transversals. We show that if $\omega(G)$ is the clique number of a chordal graph $G$, then there is a transversal of order at most $4\lceil\frac{\omega(G)}{5}\rceil$. We...
\section{Introduction} In this paper we consider the paths of maximum length among all paths in a graph. As longest paths represent the most indirect way one could travel through the graph from some place to another, we will adopt the terminology of Kapoor et al.~\cite{KapoorEtal,JobsonEtal} and refer to them as \emp...
{ "timestamp": "2020-12-15T02:27:31", "yymm": "2012", "arxiv_id": "2012.07221", "language": "en", "url": "https://arxiv.org/abs/2012.07221", "abstract": "We consider the size of the smallest set of vertices required to intersect every longest path in a chordal graph. Such sets are known as longest path tran...
https://arxiv.org/abs/1011.6646
Sparse random graphs: Eigenvalues and Eigenvectors
In this paper we prove the semi-circular law for the eigenvalues of regular random graph $G_{n,d}$ in the case $d\rightarrow \infty$, complementing a previous result of McKay for fixed $d$. We also obtain a upper bound on the infinity norm of eigenvectors of Erdős-Rényi random graph $G(n,p)$, answering a question raise...
\section{Introduction} \subsection{Overview} In this paper, we consider two models of random graphs, the Erd\H{o}s-R\'{e}nyi random graph $G(n,p)$ and the random regular graph $G_{n,d}$. Given a real number $p=p(n)$,$0\le p\le 1$, the Erd\H{o}s-R\'{e}nyi graph on a vertex set of size $n$ is obtained by drawing an ...
{ "timestamp": "2010-12-01T02:02:55", "yymm": "1011", "arxiv_id": "1011.6646", "language": "en", "url": "https://arxiv.org/abs/1011.6646", "abstract": "In this paper we prove the semi-circular law for the eigenvalues of regular random graph $G_{n,d}$ in the case $d\\rightarrow \\infty$, complementing a prev...
https://arxiv.org/abs/1609.02181
Geometry and a natural symplectic structure of phase tropical hypersurfaces
First, we define phase tropical hypersurfaces in terms of a degeneration data of smooth complex algebraic hypersurfaces in $(\mathbb{C}^*)^n$. Next, we prove that complex hyperplanes are diffeomorphic to their degeneration called phase tropical hyperplanes. More generally, using Mikhalkin's decomposition into pairs-of-...
\section{introduction} In this paper we deal with smooth algebraic hypersurfaces in the complex projective space $\mathbb{CP}^n$. So, let $V$ be a smooth hypersurface in $\mathbb{CP}^n$ of degree $d$. Recall that for a fixed degree, generically a hypersurface in the projective space is smooth and transverse to all...
{ "timestamp": "2016-09-09T02:00:39", "yymm": "1609", "arxiv_id": "1609.02181", "language": "en", "url": "https://arxiv.org/abs/1609.02181", "abstract": "First, we define phase tropical hypersurfaces in terms of a degeneration data of smooth complex algebraic hypersurfaces in $(\\mathbb{C}^*)^n$. Next, we p...
https://arxiv.org/abs/2209.09379
Characterization of Graphs With Failed Skew Zero Forcing Number of 1
Given a graph $G$, the zero forcing number of $G$, $Z(G)$, is the smallest cardinality of any set $S$ of vertices on which repeated applications of the forcing rule results in all vertices being in $S$. The forcing rule is: if a vertex $v$ is in $S$, and exactly one neighbor $u$ of $v$ is not in $S$, then $u$ is added ...
\section{Introduction} Given a graph $G$, the zero forcing number of $G$, $Z(G)$, is the smallest cardinality of any set $S$ of vertices on which repeated applications of the forcing rule results in all vertices being in $S$. The forcing rule is: if a vertex $v$ is in $S$, and exactly one neighbor $u$ of $v$ is not in ...
{ "timestamp": "2022-09-21T02:05:59", "yymm": "2209", "arxiv_id": "2209.09379", "language": "en", "url": "https://arxiv.org/abs/2209.09379", "abstract": "Given a graph $G$, the zero forcing number of $G$, $Z(G)$, is the smallest cardinality of any set $S$ of vertices on which repeated applications of the fo...
https://arxiv.org/abs/1109.2934
On the asymptotic maximal density of a set avoiding solutions to linear equations modulo a prime
Given a finite family F of linear forms with integer coefficients, and a compact abelian group G, an F-free set in G is a measurable set which does not contain solutions to any equation L(x)=0 for L in F. We denote by d_F(G) the supremum of m(A) over F-free sets A in G, where m is the normalized Haar measure on G. Our ...
\section{Introduction} Much work in arithmetic combinatorics concerns the maximal density that a subset of a finite abelian group can have if it does not contain a non-trivial solution to a given linear equation. Examples include the study of sum-free sets, where the equation to be avoided is $x_1+x_2-x_3=0$, and the ...
{ "timestamp": "2011-09-15T02:00:37", "yymm": "1109", "arxiv_id": "1109.2934", "language": "en", "url": "https://arxiv.org/abs/1109.2934", "abstract": "Given a finite family F of linear forms with integer coefficients, and a compact abelian group G, an F-free set in G is a measurable set which does not cont...
https://arxiv.org/abs/1001.4169
Stolarsky's conjecture and the sum of digits of polynomial values
Let $s_q(n)$ denote the sum of the digits in the $q$-ary expansion of an integer $n$. In 1978, Stolarsky showed that $$ \liminf_{n\to\infty} \frac{s_2(n^2)}{s_2(n)} = 0. $$ He conjectured that, as for $n^2$, this limit infimum should be 0 for higher powers of $n$. We prove and generalize this conjecture showing that fo...
\section{Introduction} Let $q\geq 2$ and denote by $s_q(n)$ the sum of digits in the $q$-ary representation of an integer $n$. In recent years, much effort has been made to get a better understanding of the distribution properties of $s_q$ regarding certain subsequences of the positive integers. We mention the ground-...
{ "timestamp": "2010-01-23T17:27:11", "yymm": "1001", "arxiv_id": "1001.4169", "language": "en", "url": "https://arxiv.org/abs/1001.4169", "abstract": "Let $s_q(n)$ denote the sum of the digits in the $q$-ary expansion of an integer $n$. In 1978, Stolarsky showed that $$ \\liminf_{n\\to\\infty} \\frac{s_2(n...
https://arxiv.org/abs/1205.4416
On the Local-Global Conjecture for integral Apollonian gaskets
We prove that a set of density one satisfies the local-global conjecture for integral Apollonian gaskets. That is, for a fixed integral, primitive Apollonian gasket, almost every (in the sense of density) admissible (passing local obstructions) integer is the curvature of some circle in the gasket.
\section{Introduction} \begin{figure} \includegraphics[width 2in]{pic.pdf} \vskip-1.25in \hskip-2.5in {\Huge -11} \vskip1in \caption{The Apollonian gasket with root quadruple $v_{0}=(-11, 21,24,28)^{t}$.} \label{fig1} \end{figure} \subsection{The Local-Global Conjecture}\ Let $\sG$ be an Apollonian gasket, see Fig...
{ "timestamp": "2013-05-15T02:00:46", "yymm": "1205", "arxiv_id": "1205.4416", "language": "en", "url": "https://arxiv.org/abs/1205.4416", "abstract": "We prove that a set of density one satisfies the local-global conjecture for integral Apollonian gaskets. That is, for a fixed integral, primitive Apollonia...
https://arxiv.org/abs/1607.08865
Law of Iterated Logarithm for random graphs
A milestone in Probability Theory is the law of the iterated logarithm (LIL), proved by Khinchin and independently by Kolmogorov in the 1920s, which asserts that for iid random variables $\{t_i\}_{i=1}^{\infty}$ with mean $0$ and variance $1$$$ \Pr \left[ \limsup_{n\rightarrow \infty} \frac{ \sum_{i=1}^n t_i }{\sigma_n...
\section{Introduction} Let $\{t_i\}_{i=1}^{\infty}$ be an infinite sequence of iid random variables with mean $0$ and variance $1$. Two key results in probability theory are the central limit theorem and the law of the iterated logarithm. The \emph{central limit theorem} (CLT) states that for $X_n:= \sum_{i=1}^n t_i$,...
{ "timestamp": "2017-10-12T02:02:51", "yymm": "1607", "arxiv_id": "1607.08865", "language": "en", "url": "https://arxiv.org/abs/1607.08865", "abstract": "A milestone in Probability Theory is the law of the iterated logarithm (LIL), proved by Khinchin and independently by Kolmogorov in the 1920s, which asser...
https://arxiv.org/abs/1009.4913
Equivalence of concentration inequalities for linear and non-linear functions
We consider a random variable $X$ that takes values in a (possibly infinite-dimensional) topological vector space $\mathcal{X}$. We show that, with respect to an appropriate "normal distance" on $\mathcal{X}$, concentration inequalities for linear and non-linear functions of $X$ are equivalent. This normal distance cor...
\section{Introduction} \label{sec:intro} It is by now almost classical that smooth enough convex functions enjoy good concentration properties; see \emph{e.g.}\ \cite{Ledoux:2001} \cite{Lugosi:2009} \cite{McDiarmid:1998} \cite{MilmanSchechtman:1986} for surveys of the literature. It is also known that convexity can ...
{ "timestamp": "2010-09-27T02:02:24", "yymm": "1009", "arxiv_id": "1009.4913", "language": "en", "url": "https://arxiv.org/abs/1009.4913", "abstract": "We consider a random variable $X$ that takes values in a (possibly infinite-dimensional) topological vector space $\\mathcal{X}$. We show that, with respect...
https://arxiv.org/abs/1905.06366
Equivalence and invariance of the chi and Hoffman constants of a matrix
We show that the following two condition measures of a full column rank matrix $A \in \mathbb{R}^{m\times n}$ are identical: the chi constant and a signed Hoffman constant. This identity is naturally suggested by the evident invariance of the chi constant under sign changes of the rows of $A$. We also show that similar...
\section{Introduction} \label{sec.intro} We show a novel equivalence between the following two condition measures of a matrix that play central roles in numerical linear algebra and in convex optimization: the chi measure~\cite{BenTT90,Diki74,Fors96,Stew89,Todd90} and the Hoffman constant~\cite{Hoff52,guler1995,KlatT9...
{ "timestamp": "2020-05-19T02:33:29", "yymm": "1905", "arxiv_id": "1905.06366", "language": "en", "url": "https://arxiv.org/abs/1905.06366", "abstract": "We show that the following two condition measures of a full column rank matrix $A \\in \\mathbb{R}^{m\\times n}$ are identical: the chi constant and a sig...
https://arxiv.org/abs/1501.01685
Spaces of regular abstract martingales
In \cite{Troitsky:05,Korostenski:08}, the authors introduced and studied the space $\mathcal M_r$ of regular martingales on a vector lattice and the space $M_r$ of bounded regular martingales on a Banach lattice. In this note, we study these two spaces from the vector lattice point of view. We show, in particular, that...
\section{The space of regular martingales on a vector lattice} Let $F$ be a vector lattice. A sequence $(E_n)$ of positive projections on $F$ such that $E_nE_m=E_{n\wedge m}$ is said to be a \term{filtration}. We will try to impose as few additional assumptions on the filtration as possible. A sequence $X=(x_n)$ in ...
{ "timestamp": "2015-01-09T02:04:35", "yymm": "1501", "arxiv_id": "1501.01685", "language": "en", "url": "https://arxiv.org/abs/1501.01685", "abstract": "In \\cite{Troitsky:05,Korostenski:08}, the authors introduced and studied the space $\\mathcal M_r$ of regular martingales on a vector lattice and the spa...
https://arxiv.org/abs/math/0601143
L-functions and higher order modular forms
It is believed that Dirichlet series with a functional equation and Euler product of a particular form are associated to holomorphic newforms on a Hecke congruence group. We perform computer algebra experiments which find that in certain cases one can associate a kind of ``higher order modular form'' to such Dirichlet ...
\section{Introduction} We investigate the relationship between degree-2 $L$-functions and modular forms. We find that degree-2 $L$-functions can be associated to functions on the upper half-plane which have similar properties to ``second order modular forms.'' Since it is conjectured that degree-2 $L$-functions can...
{ "timestamp": "2006-01-07T20:54:52", "yymm": "0601", "arxiv_id": "math/0601143", "language": "en", "url": "https://arxiv.org/abs/math/0601143", "abstract": "It is believed that Dirichlet series with a functional equation and Euler product of a particular form are associated to holomorphic newforms on a Hec...
https://arxiv.org/abs/2008.00584
Optimal rates of convergence and error localization of Gegenbauer projections
Motivated by comparing the convergence behavior of Gegenbauer projections and best approximations, we study the optimal rate of convergence for Gegenbauer projections in the maximum norm. We show that the rate of convergence of Gegenbauer projections is the same as that of best approximations under conditions of the un...
\section{Introduction}\label{sec:introduction} Orthogonal polynomial approximations, such as Gegenbauer as well as Legendre and Chebyshev approximations, play an important role in many branches of numerical analysis, including function approximations and quadrature \cite{davis1984methods,trefethen2013atap}, the re...
{ "timestamp": "2020-08-04T02:26:43", "yymm": "2008", "arxiv_id": "2008.00584", "language": "en", "url": "https://arxiv.org/abs/2008.00584", "abstract": "Motivated by comparing the convergence behavior of Gegenbauer projections and best approximations, we study the optimal rate of convergence for Gegenbauer...
https://arxiv.org/abs/2212.01211
Sometimes Two Irrational Guards are Needed
In the art gallery problem, we are given a closed polygon $P$, with rational coordinates and an integer $k$. We are asked whether it is possible to find a set (of guards) $G$ of size $k$ such that any point $p\in P$ is seen by a point in $G$. We say two points $p$, $q$ see each other if the line segment $pq$ is contain...
\section{Introduction} In the art gallery problem, we are given a closed polygon $P$, on $n$ vertices, with rational coordinates and an integer $k$. We are asked whether it is possible to find a set (of guards) $G$ of size $k$ such that any point $p\in P$ is seen by a point in $G$. We...
{ "timestamp": "2022-12-05T02:13:36", "yymm": "2212", "arxiv_id": "2212.01211", "language": "en", "url": "https://arxiv.org/abs/2212.01211", "abstract": "In the art gallery problem, we are given a closed polygon $P$, with rational coordinates and an integer $k$. We are asked whether it is possible to find a...
https://arxiv.org/abs/1812.00114
The Duality between Ideals of Multilinear Operators and Tensor Norms
We develop the duality theory between ideals of multilinear operators and tensor norms that arises from the geometric approach of $\Sigma$-operators. To this end, we introduce and develop the notions of $\Sigma$-ideals of multilinear operators and $\Sigma$-tensor norms. We establish the foundations of this theory by pr...
\section{Introduction} The theory of operator ideals, mainly developed by Pietsch in \cite{pietsch78}, is a branch of Functional Analysis that provides a systematic framework to study linear operators grouping them according to the so called ideal property. Many examples of operator ideals find applications in a wide...
{ "timestamp": "2018-12-04T02:05:50", "yymm": "1812", "arxiv_id": "1812.00114", "language": "en", "url": "https://arxiv.org/abs/1812.00114", "abstract": "We develop the duality theory between ideals of multilinear operators and tensor norms that arises from the geometric approach of $\\Sigma$-operators. To ...
https://arxiv.org/abs/2105.05732
Exact controllability to eigensolutions for evolution equations of parabolic type via bilinear control
In a separable Hilbert space $X$, we study the controlled evolution equation \begin{equation*} u'(t)+Au(t)+p(t)Bu(t)=0, \end{equation*} where $A\geq-\sigma I$ ($\sigma\geq0$) is a self-adjoint linear operator, $B$ is a bounded linear operator on $X$, and $p\in L^2_{loc}(0,+\infty)$ is a bilinear control.We give suffici...
\section{Introduction} In a separable Hilbert space $X$ consider the nonlinear control system \begin{equation}\label{u} \left\{ \begin{array}{ll} u'(t)+Au(t)+p(t)Bu(t)=0,& t>0\\\\ u(0)=u_0. \end{array}\right. \end{equation} where $A:D(A)\subset X\to X$ is a linear self-adjoint operator on $X$ such that $A\geq-\sigma I$...
{ "timestamp": "2021-05-13T02:20:59", "yymm": "2105", "arxiv_id": "2105.05732", "language": "en", "url": "https://arxiv.org/abs/2105.05732", "abstract": "In a separable Hilbert space $X$, we study the controlled evolution equation \\begin{equation*} u'(t)+Au(t)+p(t)Bu(t)=0, \\end{equation*} where $A\\geq-\\...
https://arxiv.org/abs/0809.0918
Intersecting random graphs and networks with multiple adjacency constraints: A simple example
When studying networks using random graph models, one is sometimes faced with situations where the notion of adjacency between nodes reflects multiple constraints. Traditional random graph models are insufficient to handle such situations.A simple idea to account for multiple constraints consists in taking the intersec...
\section{Introduction} \label{sec:Introduction} Graphs provide simple and useful representations for networks with the presence of an edge between a pair of nodes marking their ability to communicate with each other. Thus, for some set $V$ of nodes, an undirected graph $G \equiv (V,E)$ with edge set $E$ is defined ...
{ "timestamp": "2008-09-04T23:13:14", "yymm": "0809", "arxiv_id": "0809.0918", "language": "en", "url": "https://arxiv.org/abs/0809.0918", "abstract": "When studying networks using random graph models, one is sometimes faced with situations where the notion of adjacency between nodes reflects multiple const...
https://arxiv.org/abs/2107.14054
Detecting and diagnosing prior and likelihood sensitivity with power-scaling
Determining the sensitivity of the posterior to perturbations of the prior and likelihood is an important part of the Bayesian workflow. We introduce a practical and computationally efficient sensitivity analysis approach using importance sampling to estimate properties of posteriors resulting from power-scaling the pr...
\section{Introduction} \label{sec:intro} Bayesian inference is characterised by the derivation of a posterior from a prior and a likelihood. As the posterior is dependent on the specification of these two components, investigating its sensitivity to perturbations of the prior and likelihood is a critical step in the...
{ "timestamp": "2022-05-06T02:25:01", "yymm": "2107", "arxiv_id": "2107.14054", "language": "en", "url": "https://arxiv.org/abs/2107.14054", "abstract": "Determining the sensitivity of the posterior to perturbations of the prior and likelihood is an important part of the Bayesian workflow. We introduce a pr...
https://arxiv.org/abs/1908.10684
Downlink Analysis for the Typical Cell in Poisson Cellular Networks
Owing to its unparalleled tractability, the Poisson point process (PPP) has emerged as a popular model for the analysis of cellular networks. Considering a stationary point process of users, which is independent of the base station (BS) point process, it is well known that the typical user does not lie in the typical c...
\section{Introduction} \label{sec:Introduction} The previous decade has witnessed a significant growth in research efforts related to the modeling and analysis of cellular networks using stochastic geometry. A vast majority of these works, e.g., \cite{AndBacJ2011,DhiGanJ2012}, rely on the homogeneous PPP model for the...
{ "timestamp": "2019-08-29T02:12:15", "yymm": "1908", "arxiv_id": "1908.10684", "language": "en", "url": "https://arxiv.org/abs/1908.10684", "abstract": "Owing to its unparalleled tractability, the Poisson point process (PPP) has emerged as a popular model for the analysis of cellular networks. Considering ...
https://arxiv.org/abs/1912.11063
Does scrambling equal chaos?
Focusing on semiclassical systems, we show that the parametrically long exponential growth of out-of-time order correlators (OTOCs), also known as scrambling, does not necessitate chaos. Indeed, scrambling can simply result from the presence of unstable fixed points in phase space, even in a classically integrable mode...
\section{Saddle-dominated scrambling in Dicke model}\label{sec:dicke} \begin{figure} \centering \includegraphics[width=.8\columnwidth]{dicke.pdf} \caption{(a) The OTOC in the quantum Dicke model ($N = 40$) with $\hat{O} = \hat{p}$, for a microcanonical ensemble of 40 eigenstates around $H = -1$, and for two...
{ "timestamp": "2020-04-09T02:03:31", "yymm": "1912", "arxiv_id": "1912.11063", "language": "en", "url": "https://arxiv.org/abs/1912.11063", "abstract": "Focusing on semiclassical systems, we show that the parametrically long exponential growth of out-of-time order correlators (OTOCs), also known as scrambl...
https://arxiv.org/abs/2004.05177
Dissipation-assisted operator evolution method for capturing hydrodynamic transport
We introduce the dissipation-assisted operator evolution (DAOE) method for calculating transport properties of strongly interacting lattice systems in the high temperature regime. DAOE is based on evolving observables in the Heisenberg picture, and applying an artificial dissipation that reduces the weight on non-local...
\section{Additional data for the Ising chain and XX ladder models} \subsection{Convergence with bond dimension} In the main text, we showed that the dissipation leads to a decay of the operator entanglement at long times. Crucially, this makes the maximal operator entanglement encountered during the evolution indepe...
{ "timestamp": "2020-04-14T02:00:16", "yymm": "2004", "arxiv_id": "2004.05177", "language": "en", "url": "https://arxiv.org/abs/2004.05177", "abstract": "We introduce the dissipation-assisted operator evolution (DAOE) method for calculating transport properties of strongly interacting lattice systems in the...
https://arxiv.org/abs/1703.04973
Real interpolation with variable exponent
We present the real interpolation with variable exponent and we prove the basic properties in analogy to the classical real interpolation. More precisely, we prove that under some additional conditions, this method can be reduced to the case of fixed exponent. An application, we give the real interpolation of variable ...
\section*{{\normalsize \bf #2}}\list {[\arabic{enumi}]}{\settowidth\labelwidth{[#1]}\leftmargin\labelwidth \advance\leftmargin\labelsep \usecounter{enumi}} \def\newblock{\hskip .11em plus .33em minus -.07em} \sloppy \sfcode`\.=1000\relax} \let\endthebibliograph=\endlist \newcommand{\...
{ "timestamp": "2017-03-16T01:07:59", "yymm": "1703", "arxiv_id": "1703.04973", "language": "en", "url": "https://arxiv.org/abs/1703.04973", "abstract": "We present the real interpolation with variable exponent and we prove the basic properties in analogy to the classical real interpolation. More precisely,...
https://arxiv.org/abs/2004.11160
Calculating permutation entropy without permutations
A method for analyzing sequential data sets, similar to the permutation entropy one, is discussed. The characteristic features of this method are as follows: it preserves information about equal values, if any, in the embedding vectors; it is exempt of combinatorics; it delivers the same entropy value as does the permu...
\section{Introduction} Due to technical progress in the areas of sensors and storage devices a huge amount of raw data about time course of different processes, such as ECG, EEG, climate data recordings, stock market data have become available. These data are redundant. The data processing and classification, aimed a...
{ "timestamp": "2020-08-14T02:11:58", "yymm": "2004", "arxiv_id": "2004.11160", "language": "en", "url": "https://arxiv.org/abs/2004.11160", "abstract": "A method for analyzing sequential data sets, similar to the permutation entropy one, is discussed. The characteristic features of this method are as follo...
https://arxiv.org/abs/1002.3934
Pseudo-Riemannian metrics on closed surfaces whose geodesic flows admit nontrivial integrals quadratic in momenta, and proof of the projective Obata conjecture for two-dimensional pseudo-Riemannian metrics
We describe all pseudo-Riemannian metrics on closed surfaces whose geodesic flows admit nontrivial integrals quadratic in momenta. As an application, we solve the Beltrami problem on closed surfaces, prove the nonexistence of quadratically-superintegrable metrics of nonconstant curvature on closed surfaces, and prove t...
\section{Introduction} \subsection{Definitions and the statement of the problem} Consider a pseudo-Riemmanian metric $g=(g_{ij})$ on a surface $M^2$. A function $F:{T^*}M\to \mathbb{R}$ is called {\it an integral} of the geodesic flow of $g$, if $\{ H, F\}=0$, where $H:= \tfrac{1}{2} \sum_{i,j} g^{ij} p_ip_j:T^*...
{ "timestamp": "2010-02-20T20:34:24", "yymm": "1002", "arxiv_id": "1002.3934", "language": "en", "url": "https://arxiv.org/abs/1002.3934", "abstract": "We describe all pseudo-Riemannian metrics on closed surfaces whose geodesic flows admit nontrivial integrals quadratic in momenta. As an application, we sol...
https://arxiv.org/abs/1805.08756
Analysis of Sequential Quadratic Programming through the Lens of Riemannian Optimization
We prove that a "first-order" Sequential Quadratic Programming (SQP) algorithm for equality constrained optimization has local linear convergence with rate $(1-1/\kappa_R)^k$, where $\kappa_R$ is the condition number of the Riemannian Hessian, and global convergence with rate $k^{-1/4}$. Our analysis builds on insights...
\section{Introduction} In this paper, we consider the equality-constrained optimization problem \begin{equation} \label{problem:manopt} \begin{aligned} \minimize_{x \in \R^n} & ~~ f(x), \\ \subjectto & ~~ x \in {\mathcal M} = \{x : F(x)=0 \}, \end{aligned} \end{equation} where we assume $f : \R^n \righta...
{ "timestamp": "2019-02-01T02:08:29", "yymm": "1805", "arxiv_id": "1805.08756", "language": "en", "url": "https://arxiv.org/abs/1805.08756", "abstract": "We prove that a \"first-order\" Sequential Quadratic Programming (SQP) algorithm for equality constrained optimization has local linear convergence with r...
https://arxiv.org/abs/math/0605771
Generalized Jacobian for Functions with Infinite Dimensional Range and Domain
In this paper, locally Lipschitz functions acting between infinite dimensional normed spaces are considered. When the range is a dual space and satisfies the Radon--Nikodým property, Clarke's generalized Jacobian will be extended to this setting. Characterization and fundamental properties of the extended generalized J...
\section{\bf Introduction} The subject of nonsmooth analysis focuses on the study of a derivative-like object for nonsmooth functions. When the function is a convex real-valued, the notion of subgradient was introduced in the late fifties by Rockafellar in \cite{Roc70}, and in the references therein. Since then, the...
{ "timestamp": "2006-05-31T01:58:05", "yymm": "0605", "arxiv_id": "math/0605771", "language": "en", "url": "https://arxiv.org/abs/math/0605771", "abstract": "In this paper, locally Lipschitz functions acting between infinite dimensional normed spaces are considered. When the range is a dual space and satisf...
https://arxiv.org/abs/2009.07305
The general position number of the Cartesian product of two trees
The general position number of a connected graph is the cardinality of a largest set of vertices such that no three pairwise-distinct vertices from the set lie on a common shortest path. In this paper it is proved that the general position number is additive on the Cartesian product of two trees.
\section{Introduction} \label{sec:intro} Let $d_G(x,y)$ denote, as usual, the number of edges on a shortest $x,y$-path in $G$. A set $S$ of vertices of a connected graph $G$ is a {\em general position set} if $d_G(x,y) \ne d_G(x,z) + d_G(z,y)$ holds for every $\{x,y,z\}\in \binom{S}{3}$. The {\em general position nu...
{ "timestamp": "2020-09-17T02:00:42", "yymm": "2009", "arxiv_id": "2009.07305", "language": "en", "url": "https://arxiv.org/abs/2009.07305", "abstract": "The general position number of a connected graph is the cardinality of a largest set of vertices such that no three pairwise-distinct vertices from the se...
https://arxiv.org/abs/2108.05411
Cohomology and deformations of weighted Rota-Baxter operators
Weighted Rota-Baxter operators on associative algebras are closely related to modified Yang-Baxter equations, splitting of algebras, weighted infinitesimal bialgebras, and play an important role in mathematical physics. For any $\lambda \in {\bf k}$, we construct a differential graded Lie algebra whose Maurer-Cartan el...
\section{Introduction} Rota-Baxter operators (of weight $0$) was first appeared in the work of G. Baxter \cite{baxter} in his study of the fluctuation theory in probability. Such operators can be seen as an algebraic abstraction of the integral operator. Rota-Baxter operators on associative algebras were further studi...
{ "timestamp": "2021-08-13T02:01:49", "yymm": "2108", "arxiv_id": "2108.05411", "language": "en", "url": "https://arxiv.org/abs/2108.05411", "abstract": "Weighted Rota-Baxter operators on associative algebras are closely related to modified Yang-Baxter equations, splitting of algebras, weighted infinitesima...
https://arxiv.org/abs/quant-ph/0501177
For Distinguishing Conjugate Hidden Subgroups, the Pretty Good Measurement is as Good as it Gets
Recently Bacon, Childs and van Dam showed that the ``pretty good measurement'' (PGM) is optimal for the Hidden Subgroup Problem on the dihedral group D_n in the case where the hidden subgroup is chosen uniformly from the n involutions. We show that, for any group and any subgroup H, the PGM is the optimal one-register ...
\section{The Hidden Conjugate Problem} Consider the following special case of the Hidden Subgroup Problem, called the \emph{Hidden Conjugate Problem} in~\cite{MooreRRS04}. Let $G$ be a group, and $H$ a non-normal subgroup of $G$; denote conjugates of $H$ as $H^g = g^{-1} H g$. Then we are promised that the hidden su...
{ "timestamp": "2005-05-20T21:30:48", "yymm": "0501", "arxiv_id": "quant-ph/0501177", "language": "en", "url": "https://arxiv.org/abs/quant-ph/0501177", "abstract": "Recently Bacon, Childs and van Dam showed that the ``pretty good measurement'' (PGM) is optimal for the Hidden Subgroup Problem on the dihedra...
https://arxiv.org/abs/1307.2198
Zero forcing for sign patterns
We introduce a new variant of zero forcing - signed zero forcing. The classical zero forcing number provides an upper bound on the maximum nullity of a matrix with a given graph (i.e. zero-nonzero pattern). Our new variant provides an analo- gous bound for the maximum nullity of a matrix with a given sign pattern. This...
\section{Introduction} One of the most vibrant areas in algebraic graph theory in recent years has been the study of minimum rank/maximum nullity problems. If $G$ is a simple graph on $n$ vertices, labelled $\{1,\ldots,n\}$, let $M^{\mathbb{F}}(G)$ be the maximum possible nullity of a symmetric $n \times n$ matrix ov...
{ "timestamp": "2013-07-09T02:10:51", "yymm": "1307", "arxiv_id": "1307.2198", "language": "en", "url": "https://arxiv.org/abs/1307.2198", "abstract": "We introduce a new variant of zero forcing - signed zero forcing. The classical zero forcing number provides an upper bound on the maximum nullity of a matr...
https://arxiv.org/abs/0905.1660
Möbius numbers of some modified generalized noncrossing partitions
In this paper we will give a Möbius number of $NC^{k}(W) \setminus \bf{mins} \cup \{\hat{0} \}$ for a Coxeter group $W$ which contains an affirmative answer for the conjecture 3.7.9 in Armstrong's paper [ Generalized noncrossing partitions and combinatorics of Coxeter groups.arXiv:math/0611106].
\section{Introduction} In this paper we will prove the following theorem which is conjectured in \cite{armstrong}. \begin{thm}\label{theorem} For each finite Coxeter group $(W,S)$ with $|S| = n$ and for all positive integers $k$, the M\"obius number of $NC^{k}(W) \setminus \bf{mins} \cup \{ \widehat{0} \}$ e...
{ "timestamp": "2009-05-11T22:42:49", "yymm": "0905", "arxiv_id": "0905.1660", "language": "en", "url": "https://arxiv.org/abs/0905.1660", "abstract": "In this paper we will give a Möbius number of $NC^{k}(W) \\setminus \\bf{mins} \\cup \\{\\hat{0} \\}$ for a Coxeter group $W$ which contains an affirmative ...
https://arxiv.org/abs/2204.13936
On the total versions of 1-2-3-conjecture for graphs and hypergraphs
In 2004, Karoński, Łuczak and Thomason proposed $1$-$2$-$3$-conjecture: For every nice graph $G$ there is an edge weighting function $ w:E(G)\rightarrow\{1,2,3\} $ such that the induced vertex coloring is proper. After that, the total versions of this conjecture were suggested in the literature and recently, Kalkowski...
\section{Introduction} Through out the paper, we consider simple and undirected graphs. For a graph $G$, the notations $V(G)$ and $E(G)$ stand for the vertex set and the edge set of $G$, respectively. A graph is called \textit{nice}, if it contains no component isomorphic to $ K_2 $. Let $ G $ be a nice graph and ...
{ "timestamp": "2022-05-02T02:10:55", "yymm": "2204", "arxiv_id": "2204.13936", "language": "en", "url": "https://arxiv.org/abs/2204.13936", "abstract": "In 2004, Karoński, Łuczak and Thomason proposed $1$-$2$-$3$-conjecture: For every nice graph $G$ there is an edge weighting function $ w:E(G)\\rightarrow\...
https://arxiv.org/abs/1502.02611
Generic Regularity of Conservative Solutions to a Nonlinear Wave Equation
The paper is concerned with conservative solutions to the nonlinear wave equation $u_{tt} - c(u)\big(c(u) u_x\big)_x = 0$. For an open dense set of $C^3$ initial data, we prove that the solution is piecewise smooth in the $t$-$x$ plane, while the gradient $u_x$ can blow up along finitely many characteristic curves. The...
\section{Introduction} \setcounter{equation}{0} Consider the quasilinear second order wave equation \begin{equation}\label{1.1} u_{tt} - c(u)\big(c(u) u_x\big)_x~=~0\,, \qquad\qquad t\in [0,T], ~~x\inI\!\!R\,.\end{equation} On the wave speed $c$ we assume \begin{itemize} \item[{\bf (A)}] The map $c:I\!\!R\mapsto I\...
{ "timestamp": "2015-02-10T02:24:31", "yymm": "1502", "arxiv_id": "1502.02611", "language": "en", "url": "https://arxiv.org/abs/1502.02611", "abstract": "The paper is concerned with conservative solutions to the nonlinear wave equation $u_{tt} - c(u)\\big(c(u) u_x\\big)_x = 0$. For an open dense set of $C^3...
https://arxiv.org/abs/cs/0606056
Fast and Simple Methods For Computing Control Points
The purpose of this paper is to present simple and fast methods for computing control points for polynomial curves and polynomial surfaces given explicitly in terms of polynomials (written as sums of monomials). We give recurrence formulae w.r.t. arbitrary affine frames. As a corollary, it is amusing that we can also g...
\section{Introduction} \label{sec1} Polynomial curves and surfaces are used extensively in geometric modeling and computer aided geometric design (CAGD) in particular (see Ramshaw \cite{Ramshaw87}, Farin \cite{Farin93,Farin95}, Hoschek and Lasser \cite{Hoschek}, or Piegl and Tiller \cite{Piegl}). One of the main re...
{ "timestamp": "2006-06-13T02:47:36", "yymm": "0606", "arxiv_id": "cs/0606056", "language": "en", "url": "https://arxiv.org/abs/cs/0606056", "abstract": "The purpose of this paper is to present simple and fast methods for computing control points for polynomial curves and polynomial surfaces given explicitl...
https://arxiv.org/abs/1609.00670
An EM based Iterative Method for Solving Large Sparse Linear Systems
We propose a novel iterative algorithm for solving a large sparse linear system. The method is based on the EM algorithm. If the system has a unique solution, the algorithm guarantees convergence with a geometric rate. Otherwise, convergence to a minimal Kullback--Leibler divergence point is guaranteed. The algorithm i...
\section{Introduction} \label{sec:intro} An important problem is to find a solution to a system of linear equations \begin{equation}\label{eq:ls} Ax = b, \end{equation} where $A = (a_{ij})$ is an $m_1 \times m_2$ matrix and $b$ is an $m_1$-dimensional vector. We mainly consider the square matrix where $m_1 = m_2 = m$...
{ "timestamp": "2018-08-03T02:01:49", "yymm": "1609", "arxiv_id": "1609.00670", "language": "en", "url": "https://arxiv.org/abs/1609.00670", "abstract": "We propose a novel iterative algorithm for solving a large sparse linear system. The method is based on the EM algorithm. If the system has a unique solut...
https://arxiv.org/abs/1610.02532
On uniform closeness of local times of Markov chains and i.i.d. sequences
In this paper we consider the field of local times of a discrete-time Markov chain on a general state space, and obtain uniform (in time) upper bounds on the total variation distance between this field and the one of a sequence of $n$ i.i.d. random variables with law given by the invariant measure of that Markov chain....
\section{Introduction} \label{intro} The purpose of this paper is to compare the field of local times of a discrete-time Markov process with the corresponding field of i.i.d.\ random variables distributed according to the stationary measure of this process, in total variation distance. We mention that local times (...
{ "timestamp": "2016-10-11T02:03:00", "yymm": "1610", "arxiv_id": "1610.02532", "language": "en", "url": "https://arxiv.org/abs/1610.02532", "abstract": "In this paper we consider the field of local times of a discrete-time Markov chain on a general state space, and obtain uniform (in time) upper bounds on ...
https://arxiv.org/abs/1903.08646
Bachet's game with lottery moves
Bachet's game is a variant of the game of Nim. There are $n$ objects in one pile. Two players take turns to remove any positive number of objects not exceeding some fixed number $m$. The player who takes the last object loses. We consider a variant of Bachet's game in which each move is a lottery over set $\{1,2,\ldots...
\section{Introduction and main result} Bachet's game was formulated in~\cite{Bachet} as follows. Starting from 1, two players add one after another some integer number not exceeding 10 to the sum. The player who is the first to reach 100, wins. This game can be considered as a variant of the game of Nim \cite{Bouto...
{ "timestamp": "2019-10-16T02:04:53", "yymm": "1903", "arxiv_id": "1903.08646", "language": "en", "url": "https://arxiv.org/abs/1903.08646", "abstract": "Bachet's game is a variant of the game of Nim. There are $n$ objects in one pile. Two players take turns to remove any positive number of objects not exce...
https://arxiv.org/abs/1001.1323
Spectral clustering based on local linear approximations
In the context of clustering, we assume a generative model where each cluster is the result of sampling points in the neighborhood of an embedded smooth surface; the sample may be contaminated with outliers, which are modeled as points sampled in space away from the clusters. We consider a prototype for a higher-order ...
\section{Introduction} In a number of modern applications, the data appear to cluster near some low-dimensional structures. In the particular setting of manifold learning~\cite{Tenenbaum00ISOmap,Roweis00LLE,Belkin03,survey-kernel-spectral,DG05}, the data are assumed to lie near manifolds embedded in Euclidean space. ...
{ "timestamp": "2011-11-30T02:02:30", "yymm": "1001", "arxiv_id": "1001.1323", "language": "en", "url": "https://arxiv.org/abs/1001.1323", "abstract": "In the context of clustering, we assume a generative model where each cluster is the result of sampling points in the neighborhood of an embedded smooth sur...
https://arxiv.org/abs/1610.05355
A simple finite element method for the Stokes equations
The goal of this paper is to introduce a simple finite element method to solve the Stokes and the Navier-Stokes equations. This method is in primal velocity-pressure formulation and is so simple such that both velocity and pressure are approximated by piecewise constant functions. Implementation issues as well as error...
\section{Introduction} The Stokes problem is to seek a pair of unknown functions $({\bf u}; p)$ satisfying \begin{eqnarray} -\nu\Delta{\bf u}+\nabla p &=&{\bf f}\quad \mbox{in}\;\Omega,\label{moment}\\ \nabla\cdot{\bf u}&=&0\quad\mbox{in}\;\Omega,\label{cont}\\ {\bf u} &=& {\bf 0}\quad\mbox{on}\;\partial\Omega,\label...
{ "timestamp": "2016-10-19T02:01:01", "yymm": "1610", "arxiv_id": "1610.05355", "language": "en", "url": "https://arxiv.org/abs/1610.05355", "abstract": "The goal of this paper is to introduce a simple finite element method to solve the Stokes and the Navier-Stokes equations. This method is in primal veloci...
https://arxiv.org/abs/2012.15689
Airy eigenstates and their relation to coordinate eigenstates
We study the eigenvalue problem for a linear potential Hamiltonian and, by writing Airy equation in terms of momentum and position operators define Airy states. We give a solution of the Schrödinger equation for the symmetrical linear potential in terms of the squeeze and displacement operators. Finally, we write the u...
\section{Introduction} The study of the Airy functions has attracted a lot attention in many branches of physics and applied mathematics. This because Airy functions are eigenfunctions of a Hamiltonian with a linear potential \cite{sakurai,gea_1999}, as well as for its non-spreading and bending properties \cite{ZHUKO...
{ "timestamp": "2021-06-01T02:05:51", "yymm": "2012", "arxiv_id": "2012.15689", "language": "en", "url": "https://arxiv.org/abs/2012.15689", "abstract": "We study the eigenvalue problem for a linear potential Hamiltonian and, by writing Airy equation in terms of momentum and position operators define Airy s...
https://arxiv.org/abs/1710.03108
The structure of multiplicative tilings of the real line
Suppose $\Omega, A \subseteq \RR\setminus\Set{0}$ are two sets, both of mixed sign, that $\Omega$ is Lebesgue measurable and $A$ is a discrete set. We study the problem of when $A \cdot \Omega$ is a (multiplicative) tiling of the real line, that is when almost every real number can be uniquely written as a product $a\c...
\section{Introduction} \label{sec:intro} Tilings have long fascinated mathematicians \cite{grunbaum1986tilings}. The case where one moves a single object by translation in an abelian group (translational tiling) has proved both challenging and full of connections to Functional Analysis \cite{kolountzakis2004milano}, ...
{ "timestamp": "2017-10-10T02:15:15", "yymm": "1710", "arxiv_id": "1710.03108", "language": "en", "url": "https://arxiv.org/abs/1710.03108", "abstract": "Suppose $\\Omega, A \\subseteq \\RR\\setminus\\Set{0}$ are two sets, both of mixed sign, that $\\Omega$ is Lebesgue measurable and $A$ is a discrete set. ...
https://arxiv.org/abs/1507.02268
Optimal approximate matrix product in terms of stable rank
We prove, using the subspace embedding guarantee in a black box way, that one can achieve the spectral norm guarantee for approximate matrix multiplication with a dimensionality-reducing map having $m = O(\tilde{r}/\varepsilon^2)$ rows. Here $\tilde{r}$ is the maximum stable rank, i.e. squared ratio of Frobenius and op...
\section{Introduction}\SectionName{intro} Much recent work has successfully utilized randomized dimensionality reduction techniques to speed up solutions to linear algebra problems, with applications in machine learning, statistics, optimization, and several other domains; see the recent monographs \cite{HMT11,Mahoney1...
{ "timestamp": "2016-03-03T02:09:35", "yymm": "1507", "arxiv_id": "1507.02268", "language": "en", "url": "https://arxiv.org/abs/1507.02268", "abstract": "We prove, using the subspace embedding guarantee in a black box way, that one can achieve the spectral norm guarantee for approximate matrix multiplicatio...
https://arxiv.org/abs/1511.06404
Bounded tiles in $\mathbb{Q}_p$ are compact open sets
Any bounded tile of the field $\mathbb{Q}_p$ of $p$-adic numbers is a compact open set up to a zero Haar measure set. In this note, we give a simple and direct proof of this fact.
\section{Introduction} Let $G$ be a locally compact abelian group and let $\Omega\subset G$ be a Borel set of positive and finite Haar measure. We say that the set $\Omega$ is a {\em tile} of $G$ if there exists a set $T \subset G$ of translates such that $\sum_{t\in T} 1_\Omega(x-t) =1$ for almost all $x\in G$, ...
{ "timestamp": "2015-11-23T02:01:40", "yymm": "1511", "arxiv_id": "1511.06404", "language": "en", "url": "https://arxiv.org/abs/1511.06404", "abstract": "Any bounded tile of the field $\\mathbb{Q}_p$ of $p$-adic numbers is a compact open set up to a zero Haar measure set. In this note, we give a simple and ...
https://arxiv.org/abs/1601.07736
An eigenvalue localization theorem for stochastic matrices and its application to Randić matrices
A square matrix is called stochastic (or row-stochastic) if it is non-negative and has each row sum equal to unity. Here, we constitute an eigenvalue localization theorem for a stochastic matrix, by using its principal submatrices. As an application, we provide a suitable bound for the eigenvalues, other than unity, of...
\section{Introduction} Stochastic matrices occur in many fields of research, such as, computer-aided-geometric designs \cite{Pen}, computational biology \cite{New}, Markov chains \cite{Sene}, etc. A stochastic matrix $\s$ is irreducible if its underlying directed graph is strongly connected. In this paper, we consider...
{ "timestamp": "2016-05-02T02:03:51", "yymm": "1601", "arxiv_id": "1601.07736", "language": "en", "url": "https://arxiv.org/abs/1601.07736", "abstract": "A square matrix is called stochastic (or row-stochastic) if it is non-negative and has each row sum equal to unity. Here, we constitute an eigenvalue loca...
https://arxiv.org/abs/1010.0232
Eigenvectors for a random walk on a hyperplane arrangement
We find explicit eigenvectors for the transition matrix of a random walk due to Bidegare, Hanlon and Rockmore. This is accomplished by using Brown and Diaconis' analysis of its stationary distribution, together with some combinatorics of functions on the face lattice of a hyperplane arrangement, due to Gelfand and Varc...
\section{Introduction} In 1999, Bidegare, Hanlon and Rockmore~\cite{BHR99} introduced a simultaneous generalization of several well-studied discrete Markov chains. Let ${\mathcal A}$ be an arrangement of $n$ linear hyperplanes in $W={\mathbb R}^\ell$, and let ${\mathcal C}$ denote the set of chambers: i.e., the connec...
{ "timestamp": "2011-10-14T02:04:57", "yymm": "1010", "arxiv_id": "1010.0232", "language": "en", "url": "https://arxiv.org/abs/1010.0232", "abstract": "We find explicit eigenvectors for the transition matrix of a random walk due to Bidegare, Hanlon and Rockmore. This is accomplished by using Brown and Diaco...
https://arxiv.org/abs/2007.01218
On Koopman Operator for Burgers' Equation
We consider the flow of Burgers' equation on an open set of (small) functions in $L^2([0,1])$. We derive explicitly the Koopman decomposition of the Burgers' flow. We identify the frequencies and the coefficients of this decomposition as eigenvalues and eigenfunctionals of the Koopman operator. We prove the convergence...
\section{\label{sec:level1}Introduction} The Koopman operator is a linear operator defined by Koopman in \cite{Koopman1931} to `linearize' nonlinear flows. This tool linearly evolves a set of observables (functionals) of the system state and allows for defining a spectrum for nonlinear flows. Such a spectrum is ofte...
{ "timestamp": "2021-04-27T02:07:52", "yymm": "2007", "arxiv_id": "2007.01218", "language": "en", "url": "https://arxiv.org/abs/2007.01218", "abstract": "We consider the flow of Burgers' equation on an open set of (small) functions in $L^2([0,1])$. We derive explicitly the Koopman decomposition of the Burge...
https://arxiv.org/abs/1712.02485
The Approximate Duality Gap Technique: A Unified Theory of First-Order Methods
We present a general technique for the analysis of first-order methods. The technique relies on the construction of a duality gap for an appropriate approximation of the objective function, where the function approximation improves as the algorithm converges. We show that in continuous time enforcement of an invariant ...
\section{Introduction}\label{sec:intro} First-order optimization methods have recently gained high popularity due to their applicability to large-scale problem instances arising from modern datasets, their relatively low computational complexity, and their potential for parallelizing computation \cite{sra2012optimiza...
{ "timestamp": "2018-12-07T02:00:37", "yymm": "1712", "arxiv_id": "1712.02485", "language": "en", "url": "https://arxiv.org/abs/1712.02485", "abstract": "We present a general technique for the analysis of first-order methods. The technique relies on the construction of a duality gap for an appropriate appro...
https://arxiv.org/abs/1909.06792
Fundamental domains in ${\rm PSL}(2,{\mathbb R})$ for Fuchsian groups
In this paper, we provide a necessary and sufficient condition for a set in ${\rm PSL}(2,{\mathbb R})$ or in $T^1{\mathbb H}^2$ to be a fundamental domain for a given Fuchsian group via its respective fundamental domain in the hyperbolic plane ${\mathbb H}^2$.
\section{Introduction} Fundamental domains arise naturally in the study of group actions on topological spaces. The concept {\em fundamental domain} is used to describe a set in a topological space under a group action of which the images tessellate the whose space. The term {\em fundamental domain} is well-known in ...
{ "timestamp": "2020-10-21T02:07:01", "yymm": "1909", "arxiv_id": "1909.06792", "language": "en", "url": "https://arxiv.org/abs/1909.06792", "abstract": "In this paper, we provide a necessary and sufficient condition for a set in ${\\rm PSL}(2,{\\mathbb R})$ or in $T^1{\\mathbb H}^2$ to be a fundamental dom...
https://arxiv.org/abs/1708.07756
An undetermined time-dependent coefficient in a fractional diffusion equation
In this work, we consider a FDE (fractional diffusion equation) $${}^C D_t^\alpha u(x,t)-a(t)\mathcal{L} u(x,t)=F(x,t)$$ with a time-dependent diffusion coefficient $a(t)$. For the direct problem, given an $a(t),$ we establish the existence, uniqueness and some regularity properties with a more general domain $\Omega$ ...
\section{Introduction} \par This paper considers the fractional diffusion equation (FDE) with a continuous and positive coefficient function $a(t):$ \begin{equation}\label{fde} \begin{aligned} ^C\!D_t^{\alpha} u(x,t)-a(t)\mathcal{L} u(x,t)&=F(x,t),\ &&x\in \Omega,\ t\in (0,T];\\ u(x,t)&=0,\ &&(x,t)\in \partia...
{ "timestamp": "2017-08-28T02:05:47", "yymm": "1708", "arxiv_id": "1708.07756", "language": "en", "url": "https://arxiv.org/abs/1708.07756", "abstract": "In this work, we consider a FDE (fractional diffusion equation) $${}^C D_t^\\alpha u(x,t)-a(t)\\mathcal{L} u(x,t)=F(x,t)$$ with a time-dependent diffusion...
https://arxiv.org/abs/1710.02287
Explicit Methods for Hilbert Modular Forms of Weight 1
In this article we present an algorithm that uses the graded algebra structure of Hilbert modular forms to compute the adelic $q$-expansion of Hilbert modular forms of weight one as the quotient of Hilbert modular forms of higher weight. The main improvement to existing methods is that our algorithm can be applied...
\section{Introduction} Established methods to compute Hilbert modular forms (HMFs) are restricted to weight at least $2$. As with classical modular forms, the weight $1$ case is more intricate. However, one can use the graded algebra structure of HMFs to compute the adelic $q$-expansion of a HMF of (partial) wei...
{ "timestamp": "2017-10-09T02:04:56", "yymm": "1710", "arxiv_id": "1710.02287", "language": "en", "url": "https://arxiv.org/abs/1710.02287", "abstract": "In this article we present an algorithm that uses the graded algebra structure of Hilbert modular forms to compute the adelic $q$-expansion of Hilbert ...
https://arxiv.org/abs/1907.08646
Fair quantile regression
Quantile regression is a tool for learning conditional distributions. In this paper we study quantile regression in the setting where a protected attribute is unavailable when fitting the model. This can lead to "unfair'' quantile estimators for which the effective quantiles are very different for the subpopulations de...
\section*{Acknowledgment} Research supported in part by ONR grant N00014-12-1-0762 and NSF grant DMS-1513594. \section{Background} \label{sec:background} In this section we review the essentials of quantile regression that will be relevant to our analysis. We also briefly discuss definitions of fairness. \subsection...
{ "timestamp": "2019-07-23T02:01:02", "yymm": "1907", "arxiv_id": "1907.08646", "language": "en", "url": "https://arxiv.org/abs/1907.08646", "abstract": "Quantile regression is a tool for learning conditional distributions. In this paper we study quantile regression in the setting where a protected attribut...
https://arxiv.org/abs/2010.08023
Primes in geometric series and finite permutation groups
As a consequence of the classification of finite simple groups, the classification of permutation groups of prime degree is complete, apart from the question of when the natural degree $(q^n-1)/(q-1)$ of ${\rm L}_n(q)$ is prime. We present heuristic arguments and computational evidence to support a conjecture that for ...
\section{Introduction}\label{Intro} The study of transitive permutation groups of prime degree goes back to the work of Galois on polynomials of prime degree. It is sometimes asserted that the groups of prime degree are now completely known, as a consequence of the classification of finite simple groups. This assert...
{ "timestamp": "2020-12-08T02:05:23", "yymm": "2010", "arxiv_id": "2010.08023", "language": "en", "url": "https://arxiv.org/abs/2010.08023", "abstract": "As a consequence of the classification of finite simple groups, the classification of permutation groups of prime degree is complete, apart from the quest...
https://arxiv.org/abs/1908.08250
Coloring Hasse diagrams and disjointness graphs of curves
Given a family of curves $\mathcal{C}$ in the plane, its disjointness graph is the graph whose vertices correspond to the elements of $\mathcal{C}$, and two vertices are joined by an edge if and only if the corresponding sets are disjoint. We prove that for every positive integer $r$ and $n$, there exists a family of $...
\section{Introduction} There are two important, seemingly unrelated, concepts that play important roles in Geometric Graph Theory and in Graph Drawing: {\em Hasse diagrams} and {\em string graphs}. Hasse diagrams were introduced by Vogt~\cite{V95} at the end of the 19th century for concise representation of partial o...
{ "timestamp": "2019-08-23T02:08:12", "yymm": "1908", "arxiv_id": "1908.08250", "language": "en", "url": "https://arxiv.org/abs/1908.08250", "abstract": "Given a family of curves $\\mathcal{C}$ in the plane, its disjointness graph is the graph whose vertices correspond to the elements of $\\mathcal{C}$, and...
https://arxiv.org/abs/2002.12840
Switching Identities by Probabilistic Means
Switching identities have a long history in potential theory and stochastic analysis. In recent work of Cox and Wang, a switching identity was used to connect an optimal stopping problem and the Skorokhod embedding problem (SEP). Typically switching identies of this form are derived using deep analytic connections. In ...
\section{Introduction} \section{Introduction} Let $D$ be a rectangle of horizontal length $T$ and let $(0,x),(0,y)$ be points on the left boundary of $D$. Let $B$ be Brownian motion (started in $x$ or $y$) and write $\sigma$ for the first time at which $(t,B_t)$ leaves the rectangle. As a particular case o...
{ "timestamp": "2021-02-26T02:15:48", "yymm": "2002", "arxiv_id": "2002.12840", "language": "en", "url": "https://arxiv.org/abs/2002.12840", "abstract": "Switching identities have a long history in potential theory and stochastic analysis. In recent work of Cox and Wang, a switching identity was used to con...
https://arxiv.org/abs/1406.7651
A simple construction for a class of $p$-groups with all of their automorphisms central
We exhibit a simple construction, based on elementary linear algebra, for a class of examples of finite $p$-groups of nilpotence class $2$ all of whose automorphisms are central.
\section{Introduction} In June 2014, Marc van Leeuwen~\cite{MvL} inquired on Mathematics StackExchange whether there is a group $P$ with an element $a \in P$ such that there is no automorphism of $P$ taking $a$ to its inverse. In our answer, we noted that an example was provided by any of the many...
{ "timestamp": "2014-07-09T02:09:38", "yymm": "1406", "arxiv_id": "1406.7651", "language": "en", "url": "https://arxiv.org/abs/1406.7651", "abstract": "We exhibit a simple construction, based on elementary linear algebra, for a class of examples of finite $p$-groups of nilpotence class $2$ all of whose auto...
https://arxiv.org/abs/0804.4042
Uncorrectable Errors of Weight Half the Minimum Distance for Binary Linear Codes
A lower bound on the number of uncorrectable errors of weight half the minimum distance is derived for binary linear codes satisfying some condition. The condition is satisfied by some primitive BCH codes, extended primitive BCH codes, Reed-Muller codes, and random linear codes. The bound asymptotically coincides with ...
\section{Introduction} For a binary linear code, correctable errors we consider here are binary errors correctable by the minimum distance decoding, which performs a maximum likelihood decoding for binary symmetric channels. Syndrome decoding is one of the minimum distance decoding. In syndrome decoding, the correctabl...
{ "timestamp": "2008-04-30T10:25:57", "yymm": "0804", "arxiv_id": "0804.4042", "language": "en", "url": "https://arxiv.org/abs/0804.4042", "abstract": "A lower bound on the number of uncorrectable errors of weight half the minimum distance is derived for binary linear codes satisfying some condition. The co...
https://arxiv.org/abs/1810.06774
Intersections of subcomplexes in non-positively curved 2-dimensional complexes
Let $X$ be a contractible $2$-complex which is a union of two contractible subcomplexes $Y$ and $Z.$ Is the intersection $Y\cap Z$ contractible as well? In this note, we prove that the inclusion-induced map $\pi _{1}(Y\cap Z)\rightarrow \pi _{1}(Z)$ is injective if $Y$ is $\pi _{1}$-injective subcomplex in a locally CA...
\section{Introduction} As a motivation, we consider the following problem. \begin{problem} \label{prob1}Let $X$ be a contractible $2$-complex which is a union of two contractible subcomplexes $Y$ and $Z.$ Is the intersection $Y\cap Z$ contractible as well? \end{problem} A higher-dimensional version of this...
{ "timestamp": "2018-10-17T02:05:48", "yymm": "1810", "arxiv_id": "1810.06774", "language": "en", "url": "https://arxiv.org/abs/1810.06774", "abstract": "Let $X$ be a contractible $2$-complex which is a union of two contractible subcomplexes $Y$ and $Z.$ Is the intersection $Y\\cap Z$ contractible as well? ...
https://arxiv.org/abs/1309.0906
On a Curious Biconditional Involving Divisors of Odd Perfect Numbers
We investigate the implications of a curious biconditional involving divisors of odd perfect numbers, if Dris conjecture that $q^k < n$ holds, where $q^k n^2$ is an odd perfect number with Euler prime $q$. We then show that this biconditional holds unconditionally. Lastly, we prove that the inequality $q<n$ holds uncon...
\section{Introduction} If $J$ is a positive integer, then we write $\sigma(J)$ for the sum of the divisors of $J$. A number $L$ is \emph{perfect} if $\sigma(L)=2L$. An even perfect number $M$ is said to be given in \emph{Euclidean form} if $$M = (2^p - 1)\cdot{2^{p - 1}}$$ where $p$ and $2^p - 1$ are primes....
{ "timestamp": "2015-06-17T02:06:51", "yymm": "1309", "arxiv_id": "1309.0906", "language": "en", "url": "https://arxiv.org/abs/1309.0906", "abstract": "We investigate the implications of a curious biconditional involving divisors of odd perfect numbers, if Dris conjecture that $q^k < n$ holds, where $q^k n^...
https://arxiv.org/abs/1403.5776
Lyubeznik numbers for nonsingular projective varieties
In this paper, we determine completely the Lyubeznik numbers $\lambda_{i,j}(A)$ of the local ring $A$ at the vertex of the affine cone over a nonsingular projective variety $V$, where $V$ is defined over a field of characteristic zero, in terms of the dimensions of the algebraic de Rham cohomology spaces of $V$. In par...
\section{Introduction} Let $A$ be a local ring that admits a surjection from an $m$-dimensional local ring $(R, \mathfrak{m})$ containing its residue field $k$, and let $I \subset R$ be the kernel of the surjection. (All rings in this paper are commutative and have an identity.) For non-negative integers $i$ and $j$,...
{ "timestamp": "2014-10-16T02:12:30", "yymm": "1403", "arxiv_id": "1403.5776", "language": "en", "url": "https://arxiv.org/abs/1403.5776", "abstract": "In this paper, we determine completely the Lyubeznik numbers $\\lambda_{i,j}(A)$ of the local ring $A$ at the vertex of the affine cone over a nonsingular p...
https://arxiv.org/abs/1407.6956
The $c$-map, Tits Satake subalgebras and the search for $\mathcal{N}=2$ inflaton potentials
In this paper we address the general problem of including inflationary models exhibiting Starobinsky-like potentials into (symmetric) $\mathcal{N}=2$ supergravities. This is done by gauging suitable abelian isometries of the hypermultiplet sector and then truncating the resulting theory to a single scalar field. By usi...
\part{\sc Introducing the subject and motivations} The present one is a research paper and it contains some new original results. These latter are mostly of mathematical-geometrical character and in our opinion they might be of some interest both for the mathematical scientific community, as well as for that of the ...
{ "timestamp": "2014-07-28T02:10:54", "yymm": "1407", "arxiv_id": "1407.6956", "language": "en", "url": "https://arxiv.org/abs/1407.6956", "abstract": "In this paper we address the general problem of including inflationary models exhibiting Starobinsky-like potentials into (symmetric) $\\mathcal{N}=2$ super...
https://arxiv.org/abs/1211.5218
Multi-frequency Calderon-Zygmund analysis and connexion to Bochner-Riesz multipliers
In this work, we describe several results exhibited during a talk at the El Escorial 2012 conference. We aim to pursue the development of a multi-frequency Calderon-Zygmund analysis introduced in [9]. We set a definition of general multi-frequency Calderon-Zygmund operator. Unweighted estimates are obtained using the c...
\section{Notations and preliminaries} Let us consider the Euclidean space $\rn$ equipped with the Lebesgue measure $dx$ and its Euclidean distance $|x-y|$. Given a ball $Q\subset\rn$ we denote its center by $c(Q)$ and its radius by $r_Q$. For any $\lambda>1$, we denote by $\lambda\,Q:=B(c(Q),\lambda r_Q)$. We writ...
{ "timestamp": "2013-05-02T02:01:05", "yymm": "1211", "arxiv_id": "1211.5218", "language": "en", "url": "https://arxiv.org/abs/1211.5218", "abstract": "In this work, we describe several results exhibited during a talk at the El Escorial 2012 conference. We aim to pursue the development of a multi-frequency ...
https://arxiv.org/abs/2104.05870
Numerical viscosity solutions to Hamilton-Jacobi equations via a Carleman estimate and the convexification method
We propose a globally convergent numerical method, called the convexification, to numerically compute the viscosity solution to first-order Hamilton-Jacobi equations through the vanishing viscosity process where the viscosity parameter is a fixed small number. By convexification, we mean that we employ a suitable Carle...
\section{Introduction} The aim of this paper is to compute viscosity solutions to a large class of Hamilton-Jacobi equations possibly involving nonconvex Hamiltonians. The key ingredient for us to reach this achievement is the use of a new Carleman estimate and the convexification method. This method is only applic...
{ "timestamp": "2021-11-08T02:05:06", "yymm": "2104", "arxiv_id": "2104.05870", "language": "en", "url": "https://arxiv.org/abs/2104.05870", "abstract": "We propose a globally convergent numerical method, called the convexification, to numerically compute the viscosity solution to first-order Hamilton-Jacob...
https://arxiv.org/abs/1307.6477
On construction and analysis of sparse random matrices and expander graphs with applications to compressed sensing
We revisit the probabilistic construction of sparse random matrices where each column has a fixed number of nonzeros whose row indices are drawn uniformly at random. These matrices have a one-to-one correspondence with the adjacency matrices of lossless expander graphs. We present tail bounds on the probability that th...
\section{Introduction} \section{Introduction}\label{sec:intro} Sparse matrices are particularly useful in applied and computational mathematics because of their low storage complexity and fast implementation as compared to dense matrices. Of late, significant progress has been made to incorporate sparse matrices in c...
{ "timestamp": "2013-07-25T02:08:22", "yymm": "1307", "arxiv_id": "1307.6477", "language": "en", "url": "https://arxiv.org/abs/1307.6477", "abstract": "We revisit the probabilistic construction of sparse random matrices where each column has a fixed number of nonzeros whose row indices are drawn uniformly a...
https://arxiv.org/abs/1202.3183
Zeta functions for function fields
We introduce new non-abelian zeta functions for curves defined over finite fields. There are two types, i.e., pure non-abelian zetas defined using semi-stable bundles, and group zetas defined for pairs consisting of (reductive group, maximal parabolic subgroup). Basic properties such as rationality and functional equat...
\section{Pure Non-Abelian Zeta Functions} Non-Abelian zeta functions for function fields were introduced in [W1] about 10 years ago. However, due to the lack of the Riemann Hypothesis, we have faced some essential difficulties. Recently, with an old paper of Drinfeld ([D]) on counting rank two cuspidal $\mathbb Q_l...
{ "timestamp": "2012-02-21T02:00:32", "yymm": "1202", "arxiv_id": "1202.3183", "language": "en", "url": "https://arxiv.org/abs/1202.3183", "abstract": "We introduce new non-abelian zeta functions for curves defined over finite fields. There are two types, i.e., pure non-abelian zetas defined using semi-stab...
https://arxiv.org/abs/1804.05985
Applications of Integer and Semi-Infinite Programming to the Integer Chebyshev Problem
We consider the integer Chebyshev problem, that of minimizing the supremum norm over polynomials with integer coefficients on the interval $[0,1]$. We implement algorithms from semi-infinite programming and a branch and bound algorithm to improve on previous methods for finding integer Chebyshev polynomials of degree $...
\section{Introduction} \subsection{The Integer Chebyshev Problem} The supremum norm of a polynomial $p$ over an interval $I$ is defined as \begin{equation} \|p(x)\|_I=\sup_{x\in I}|p(x)| \end{equation} Let $\mathbb{Z}_n[x]$ denote the polynomials of degree at most $n$ with integer coefficients. The integer Chebyshev p...
{ "timestamp": "2018-10-29T01:06:30", "yymm": "1804", "arxiv_id": "1804.05985", "language": "en", "url": "https://arxiv.org/abs/1804.05985", "abstract": "We consider the integer Chebyshev problem, that of minimizing the supremum norm over polynomials with integer coefficients on the interval $[0,1]$. We imp...
https://arxiv.org/abs/2003.07852
String topology of finite groups of Lie type
We show that the mod $\ell$ cohomology of any finite group of Lie type in characteristic $p$ different from $\ell$ admits the structure of a module over the mod $\ell$ cohomology of the free loop space of the classifying space $BG$ of the corresponding compact Lie group $G$, via ring and module structures constructed f...
\section{Introduction} For large primes $\ell$, the mod $\ell$ cohomology ring of a finite group of Lie type ${\mathbf G}({\mathbb {F}}_q)$ over a finite field ${\mathbb {F}}_q$ of characteristic $p\neq \ell$ has been known since Quillen \cite[\S2]{quillen71icm}: it is the tensor product of a polynomial algebra and ...
{ "timestamp": "2020-03-18T01:15:28", "yymm": "2003", "arxiv_id": "2003.07852", "language": "en", "url": "https://arxiv.org/abs/2003.07852", "abstract": "We show that the mod $\\ell$ cohomology of any finite group of Lie type in characteristic $p$ different from $\\ell$ admits the structure of a module over...
https://arxiv.org/abs/1810.03772
The existence of perfect codes in Doob graphs
We solve the problem of existence of perfect codes in the Doob graph. It is shown that 1-perfect codes in the Doob graph D(m,n) exist if and only if 6m+3n+1 is a power of 2; that is, if the size of a 1-ball divides the number of vertices. Keywords: perfect codes, distance-regular graphs, Doob graphs, Eisenstein-Jacobi ...
\section{Introduction} {T}{he} codes in Doob graphs are special cases of codes over Eisenstein--Jacobi integers, see, e.g., \cite{Huber94,MSBG:2008}, which can be used for the information transmission in the channels with two-dimensional or complex-valued modulation. The vertices of a Doob graph can be considered as wo...
{ "timestamp": "2018-10-10T02:04:13", "yymm": "1810", "arxiv_id": "1810.03772", "language": "en", "url": "https://arxiv.org/abs/1810.03772", "abstract": "We solve the problem of existence of perfect codes in the Doob graph. It is shown that 1-perfect codes in the Doob graph D(m,n) exist if and only if 6m+3n...
https://arxiv.org/abs/1210.1252
On Permutation Binomials over Finite Fields
Let $\mathbb{F}_{q}$ be the finite field of characteristic $p$ containing $q = p^{r}$ elements and $f(x)=ax^{n} + x^{m}$ a binomial with coefficients in this field. If some conditions on the gcd of $n-m$ an $q-1$ are satisfied then this polynomial does not permute the elements of the field. We prove in particular that ...
\section{Introduction} Let $\mathbb{F}_{q}$ be the finite field of characteristic $p$ containing $q = p^{r}$ elements. A polynomial $f(x) \in \mathbb{F}_{q}$ is called a permutation polynomial of $\mathbb{F}_{q}$ if the induced map $f: \mathbb{F}_{q} \rightarrow \mathbb{F}_{q}$ is one to one. The study of permutation p...
{ "timestamp": "2012-10-05T02:01:10", "yymm": "1210", "arxiv_id": "1210.1252", "language": "en", "url": "https://arxiv.org/abs/1210.1252", "abstract": "Let $\\mathbb{F}_{q}$ be the finite field of characteristic $p$ containing $q = p^{r}$ elements and $f(x)=ax^{n} + x^{m}$ a binomial with coefficients in th...
https://arxiv.org/abs/2203.05418
On a generalized Aviles-Giga functional: compactness, zero-energy states, regularity estimates and energy bounds
Given any strictly convex norm $\|\cdot\|$ on $\mathbb{R}^2$ that is $C^1$ in $\mathbb{R}^2\setminus\{0\}$, we study the generalized Aviles-Giga functional \[I_{\epsilon}(m):=\int_{\Omega} \left(\epsilon \left|\nabla m\right|^2 + \frac{1}{\epsilon}\left(1-\|m\|^2\right)^2\right) \, dx,\] for $\Omega\subset\mathbb R^2$ ...
\section{Introduction} The Aviles-Giga functional \begin{align*} AG_\varepsilon(u)=\int_\Omega \left( \varepsilon |\nabla^2 u|^2 +\frac 1\varepsilon (1-| \nabla u|^2)^2\right)\, dx,\quad\Omega\subset{\mathbb R}^2,\quad u\colon\Omega\to{\mathbb R}, \end{align*} is a second order functional that (subject to appropria...
{ "timestamp": "2022-03-11T02:23:22", "yymm": "2203", "arxiv_id": "2203.05418", "language": "en", "url": "https://arxiv.org/abs/2203.05418", "abstract": "Given any strictly convex norm $\\|\\cdot\\|$ on $\\mathbb{R}^2$ that is $C^1$ in $\\mathbb{R}^2\\setminus\\{0\\}$, we study the generalized Aviles-Giga f...
https://arxiv.org/abs/1306.2423
Numerical Radii for Tensor Products of Matrices
For $n$-by-$n$ and $m$-by-$m$ complex matrices $A$ and $B$, it is known that the inequality $w(A\otimes B)\le\|A\|w(B)$ holds, where $w(\cdot)$ and $\|\cdot\|$ denote, respectively, the numerical radius and the operator norm of a matrix. In this paper, we consider when this becomes an equality. We show that (1) if $\|A...
\section{Introduction and Preliminaries} For any $n$-by-$n$ complex matrix $A$, its \emph{numerical range} $W(A)$ is, by definition, the subset $\{\langle Ax, x\rangle : x\in \mathbb{C}^n, \|x\|=1\}$ of the complex plane $\mathbb{C}$, where $\langle\cdot, \cdot\rangle$ and $\|\cdot\|$ denote the standard inner pro...
{ "timestamp": "2013-06-12T02:01:19", "yymm": "1306", "arxiv_id": "1306.2423", "language": "en", "url": "https://arxiv.org/abs/1306.2423", "abstract": "For $n$-by-$n$ and $m$-by-$m$ complex matrices $A$ and $B$, it is known that the inequality $w(A\\otimes B)\\le\\|A\\|w(B)$ holds, where $w(\\cdot)$ and $\\...
https://arxiv.org/abs/0910.3442
Counting the spanning trees of a directed line graph
The line graph LG of a directed graph G has a vertex for every edge of G and an edge for every path of length 2 in G. In 1967, Knuth used the Matrix-Tree Theorem to prove a formula for the number of spanning trees of LG, and he asked for a bijective proof. In this paper, we give a bijective proof of a generating functi...
\section{Introduction} \label{introduction} In a directed graph $G=(V,E)$, each edge $e\in E$ is directed from its source $s(e)$ to its target $t(e)$. The directed line graph $\mathcal{L} G$ of $G$ with vertex set $E$, and with an edge $(e,f)$ for every pair of edges in $G$ such that $t(e)=s(f)$. A spanning tree of $...
{ "timestamp": "2009-12-04T20:37:51", "yymm": "0910", "arxiv_id": "0910.3442", "language": "en", "url": "https://arxiv.org/abs/0910.3442", "abstract": "The line graph LG of a directed graph G has a vertex for every edge of G and an edge for every path of length 2 in G. In 1967, Knuth used the Matrix-Tree Th...
https://arxiv.org/abs/1610.04122
Modules and Structures of Planar Upper Triangular Rook Monoids
In this paper, we discuss modules and structures of the planar upper triangular rook monoid B_n. We first show that the order of B_n is a Catalan number, then we investigate the properties of a module V over B_n generated by a set of elements v_S indexed by the power set of {1, ..., n}. We find that every nonzero submo...
\section{Introduction} A matrix is a rook matrix if each entry is $0$ or $1$ and each row and column have at most one $1$. A rook matrix $A$ is {\it planar} or {\it order preserving} if the matrix obtained from $A$ by deleting all the zero rows and all the zero columns is an identity matrix. The structure and repre...
{ "timestamp": "2016-10-14T02:06:09", "yymm": "1610", "arxiv_id": "1610.04122", "language": "en", "url": "https://arxiv.org/abs/1610.04122", "abstract": "In this paper, we discuss modules and structures of the planar upper triangular rook monoid B_n. We first show that the order of B_n is a Catalan number, ...
https://arxiv.org/abs/1212.5934
Some Bounds on the Rainbow Connection Number of 3-, 4- and 5-connected Graphs
The rainbow connection number, $rc(G)$, of a connected graph $G$ is the minimum number of colors needed to color its edges so that every pair of vertices is connected by at least one path in which no two edges are colored the same. We show that for $\kappa =3$ or $\kappa = 4$, every $\kappa$-connected graph $G$ on $n$ ...
\section{Introduction} Let $G$ be a simple, undirected, connected graph on $n$ vertices, such that its edges are colored by some edge coloring $c$. We say that a path $P$ in $G$ is a \textit{rainbow path} if no two edges of $P$ are the same color. We say that the edge-colored graph $(G, c)$ is \textit{rainbow-connected...
{ "timestamp": "2012-12-27T02:03:17", "yymm": "1212", "arxiv_id": "1212.5934", "language": "en", "url": "https://arxiv.org/abs/1212.5934", "abstract": "The rainbow connection number, $rc(G)$, of a connected graph $G$ is the minimum number of colors needed to color its edges so that every pair of vertices is...
https://arxiv.org/abs/2302.07595
Macaulay's theorem for vector-spread algebras
Let $S=K[x_1,\dots,x_n]$ be the standard graded polynomial ring, with $K$ a field, and let ${\bf t}=(t_1,\ldots,t_{d-1})\in{\mathbb{Z}}_{\ge 0}^{d-1}$, $d\ge 2$, be a $(d-1)$-tuple whose entries are non negative integers. To a ${\bf t}$-spread ideal $I$ in $S$, we associate a unique $f_{\bf t}$-vector and we prove that...
\section*{Introduction} One of the main well--studied and important numerical invariant of a graded ideal in a standard graded polynomial ring is its Hilbert function which gives the sizes of the graded components of the ideal. There is an extensive literature on this topic (see, for instance, \cite{JT} and the refe...
{ "timestamp": "2023-02-21T02:30:57", "yymm": "2302", "arxiv_id": "2302.07595", "language": "en", "url": "https://arxiv.org/abs/2302.07595", "abstract": "Let $S=K[x_1,\\dots,x_n]$ be the standard graded polynomial ring, with $K$ a field, and let ${\\bf t}=(t_1,\\ldots,t_{d-1})\\in{\\mathbb{Z}}_{\\ge 0}^{d-1...
https://arxiv.org/abs/2209.06304
A note on conjectures generalizing the road colouring theorem
The road colouring theorem characterizes the class of strongly connected directed graphs with constant out-degree that admit a synchronizing road colouring. The subject of this paper is a pair of related conjectures that generalize the road colouring theorem to graphs with non-constant out-degree; we give reasons to be...
\section{Introduction} The road colouring theorem characterizes the class of strongly connected directed graphs with constant out-degree that admit a synchronizing road colouring. The subject of this paper is a pair of related conjectures that generalize the road colouring theorem to graphs with non-constant out-degree...
{ "timestamp": "2022-09-15T02:03:20", "yymm": "2209", "arxiv_id": "2209.06304", "language": "en", "url": "https://arxiv.org/abs/2209.06304", "abstract": "The road colouring theorem characterizes the class of strongly connected directed graphs with constant out-degree that admit a synchronizing road colourin...
https://arxiv.org/abs/2203.11550
Running Time Analysis of the Non-dominated Sorting Genetic Algorithm II (NSGA-II) using Binary or Stochastic Tournament Selection
Evolutionary algorithms (EAs) have been widely used to solve multi-objective optimization problems, and have become the most popular tool. However, the theoretical foundation of multi-objective EAs (MOEAs), especially the essential theoretical aspect, i.e., running time analysis, has been still largely underdeveloped. ...
\section{Introduction} Multi-objective optimization~\cite{Steuer86}, which requires to optimize several objective functions simultaneously, arises in many areas. Since the objectives are usually conflicting, there doesn't exist a single solution which can perform well on all these objective functions. Thus, the go...
{ "timestamp": "2022-03-23T01:20:53", "yymm": "2203", "arxiv_id": "2203.11550", "language": "en", "url": "https://arxiv.org/abs/2203.11550", "abstract": "Evolutionary algorithms (EAs) have been widely used to solve multi-objective optimization problems, and have become the most popular tool. However, the th...
https://arxiv.org/abs/1909.06221
A proximal average for prox-bounded functions
In this work, we construct a proximal average for two prox-bounded functions, which recovers the classical proximal average for two convex functions. The new proximal average transforms continuously in epi-topology from one proximal hull to the other. When one of the functions is differentiable, the new proximal averag...
\section{Introduction} The proximal average provides a novel technique for averaging convex functions, see \cite{convmono,proxbas}. The proximal average has been used widely in applications such as machine learning \cite{reidwill,Yu13a}, optimization \cite{resaverage,wolenski,boyd14,planwang2016,zaslav}, matrix analy...
{ "timestamp": "2019-09-16T02:11:59", "yymm": "1909", "arxiv_id": "1909.06221", "language": "en", "url": "https://arxiv.org/abs/1909.06221", "abstract": "In this work, we construct a proximal average for two prox-bounded functions, which recovers the classical proximal average for two convex functions. The ...
https://arxiv.org/abs/1402.4911
Finite element eigenvalue enclosures for the Maxwell operator
We propose employing the extension of the Lehmann-Maehly-Goerisch method developed by Zimmermann and Mertins, as a highly effective tool for the pollution-free finite element computation of the eigenfrequencies of the resonant cavity problem on a bounded region. This method gives complementary bounds for the eigenfrequ...
\section{Introduction} The framework developed by Zimmermann and Mertins \cite{ZM95} which generalizes the Lehmann-Maehly-Goerisch method \cite{1985Goerisch2,1980Goerisch,1949Lehmann,1950Lehmann,1952Maehly} (also \cite[Chapter~4.11]{1974Weinberger}), is a reliable tool for the numerical computation of bounds for the e...
{ "timestamp": "2014-03-03T19:57:26", "yymm": "1402", "arxiv_id": "1402.4911", "language": "en", "url": "https://arxiv.org/abs/1402.4911", "abstract": "We propose employing the extension of the Lehmann-Maehly-Goerisch method developed by Zimmermann and Mertins, as a highly effective tool for the pollution-f...
https://arxiv.org/abs/1808.06525
First Occurring Singularities of Functions in Symplectic Semi-Space
We explain how a classical theorem by Arnol'd and Melrose on non-singular functions on a symplectic manifold with boundary can be proved in few lines, and we use the same method to obtain a new result, which is a normal form with functional invariants for the first occurring singularities
\section{Introduction and main results} \label{sec-intr-results} All objects in the paper are either $C^{\infty}$ or analytic germs at $0$. By a symplectic semi-space we mean the symplectic space $(\mathbb{R}^{2n},\omega )$ where $\omega $ is a symplectic form, endowed with a smooth hypersurface $\mathcal H$, which...
{ "timestamp": "2018-08-21T02:18:16", "yymm": "1808", "arxiv_id": "1808.06525", "language": "en", "url": "https://arxiv.org/abs/1808.06525", "abstract": "We explain how a classical theorem by Arnol'd and Melrose on non-singular functions on a symplectic manifold with boundary can be proved in few lines, and...
https://arxiv.org/abs/1905.10355
Taylor expansions of groups and filtered-formality
Let $G$ be a finitely generated group, and let $\Bbbk{G}$ be its group algebra over a field of characteristic $0$. A Taylor expansion is a certain type of map from $G$ to the degree completion of the associated graded algebra of $\Bbbk{G}$ which generalizes the Magnus expansion of a free group. The group $G$ is said to...
\section{Introduction} \label{sect:intro} \subsection{Expansions of groups} \label{intro:exp} Group expansions were first introduced by Magnus in \cite{Magnus35}, in order to show that finitely generated free groups are residually nilpotent. This technique has been generalized and used in many ways. For instance,...
{ "timestamp": "2019-11-20T02:18:30", "yymm": "1905", "arxiv_id": "1905.10355", "language": "en", "url": "https://arxiv.org/abs/1905.10355", "abstract": "Let $G$ be a finitely generated group, and let $\\Bbbk{G}$ be its group algebra over a field of characteristic $0$. A Taylor expansion is a certain type o...
https://arxiv.org/abs/1905.03456
Expanding polynomials on sets with few products
In this note, we prove that if $A$ is a finite set of real numbers such that $|AA| = K|A|$, then for every polynomial $f \in \mathbb{R}[x,y]$ we have that $|f(A,A)| = \Omega_{K,\operatorname{deg} f}(|A|^2)$, unless $f$ is of the form $f(x,y) = g(M(x,y))$ for some monomial $M$ and some univariate polynomial $g$.
\section{Introduction} \label{intro} Given polynomials $f\in \ensuremath{\mathbb R}[x]$ and $g\in \ensuremath{\mathbb R}[x,y]$, and sets $A,B\subset \ensuremath{\mathbb R}$, we write \[ f(A) = \{f(a) :\ a\in A \} \ \text{ and } \ g(A,B) = \{g(a,b) :\ a\in A,\ b\in B\}. \] That is, $g(A,B)$ is the set of distinct values...
{ "timestamp": "2019-05-10T02:09:34", "yymm": "1905", "arxiv_id": "1905.03456", "language": "en", "url": "https://arxiv.org/abs/1905.03456", "abstract": "In this note, we prove that if $A$ is a finite set of real numbers such that $|AA| = K|A|$, then for every polynomial $f \\in \\mathbb{R}[x,y]$ we have th...
https://arxiv.org/abs/1801.00082
An HDG Method for Distributed Control of Convection Diffusion PDEs
We propose a hybridizable discontinuous Galerkin (HDG) method to approximate the solution of a distributed optimal control problem governed by an elliptic convection diffusion PDE. We derive optimal a priori error estimates for the state, adjoint state, their fluxes, and the optimal control. We present 2D and 3D numeri...
\section{Introduction} \label{intro} We consider the following distributed control problem: Minimize the functional \begin{align} \min J(u)=\frac{1}{2}\| y- y_{d}\|^2_{L^{2}(\Omega)}+\frac{\gamma}{2}\|u\|^2_{L^{2}(\Omega)}, \quad \gamma>0, \label{cost1} \end{align} subject to \begin{equation}\label{Ori_problem} \beg...
{ "timestamp": "2018-01-03T02:02:32", "yymm": "1801", "arxiv_id": "1801.00082", "language": "en", "url": "https://arxiv.org/abs/1801.00082", "abstract": "We propose a hybridizable discontinuous Galerkin (HDG) method to approximate the solution of a distributed optimal control problem governed by an elliptic...
https://arxiv.org/abs/math/0608746
A parabolic free boundary problem with Bernoulli type condition on the free boundary
Consider the parabolic free boundary problem $$ \Delta u - \partial_t u = 0 \textrm{in} \{u>0\}, |\nabla u|=1 \textrm{on} \partial\{u>0\} . $$ For a realistic class of solutions, containing for example {\em all} limits of the singular perturbation problem $$\Delta u_\epsilon - \partial_t u_\epsilon = \beta_\epsilon(u_\...
\section{Introduction} The parabolic free boundary problem \begin{equation}\label{bernoulli}\Delta u - \partial_t u = 0 \textrm{ in } \{ u>0\}\> , \> |\nabla u|=1 \textrm{ on } \partial\{ u>0\}\end{equation} has originally been derived as singular limit from a model for the propagation of equidiffusional premixed flame...
{ "timestamp": "2006-08-30T10:06:23", "yymm": "0608", "arxiv_id": "math/0608746", "language": "en", "url": "https://arxiv.org/abs/math/0608746", "abstract": "Consider the parabolic free boundary problem $$ \\Delta u - \\partial_t u = 0 \\textrm{in} \\{u>0\\}, |\\nabla u|=1 \\textrm{on} \\partial\\{u>0\\} . ...
https://arxiv.org/abs/1209.6044
Bounded Geometry and Characterization of post-singularly Finite $(p,q)$-Exponential Maps
In this paper we define a topological class of branched covering maps of the plane called {\em topological exponential maps of type $(p,q)$} and denoted by $\TE_{p,q}$, where $p\geq 0$ and $q\geq 1$. We follow the framework given in \cite{Ji} to study the problem of combinatorially characterizing an entire map $P e^{Q}...
\section{Introduction} \label{sec:intro} Thurston asked the question ``when can we realize a given branched covering map as a holomorphic map in such a way that the post-critical sets correspond?" and answered it for post-critically finite degree $d$ branched covers of the sphere~\cite{T,DH}. His theorem is that a p...
{ "timestamp": "2013-09-17T02:02:21", "yymm": "1209", "arxiv_id": "1209.6044", "language": "en", "url": "https://arxiv.org/abs/1209.6044", "abstract": "In this paper we define a topological class of branched covering maps of the plane called {\\em topological exponential maps of type $(p,q)$} and denoted by...