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https://en.wikipedia.org/wiki/North%20Korean%20abductions%20of%20South%20Koreans
An estimated 84,532 South Koreans were taken to North Korea during the Korean War. In addition, South Korean statistics claim that, since the Korean Armistice Agreement in 1953, about 3,800 people have been abducted by North Korea (the vast majority in the late 1970s), 489 of whom were still being held in 2006. Termin...
https://en.wikipedia.org/wiki/Mikata%20District%2C%20Hy%C5%8Dgo
is a district located in Hyōgo Prefecture, Japan. As of the April 1, 2005 merger (but using 2003 population statistics), the district has an estimated population of 40,084 and a density of 66 persons per km2. The total area is 610.02 km2. Towns and villages Kami Shin'onsen Mergers On April 1, 2005 the towns of Mikat...
https://en.wikipedia.org/wiki/Max%20Dehn
Max Wilhelm Dehn (November 13, 1878 – June 27, 1952) was a German mathematician most famous for his work in geometry, topology and geometric group theory. Dehn's early life and career took place in Germany. However, he was forced to retire in 1935 and eventually fled Germany in 1939 and emigrated to the United States....
https://en.wikipedia.org/wiki/BGM
BGM can refer to: Locations Boddington Gold Mine, a gold mine in Western Australia. Mathematics Bayesian Graphical Model, a form of probability model. Brace Gatarek Musiela LIBOR market model: a finance model, also called BGM in reference to some of its inventors Medicine Blood glucose monitoring, or the device used...
https://en.wikipedia.org/wiki/Dirichlet%20problem
In mathematics, a Dirichlet problem is the problem of finding a function which solves a specified partial differential equation (PDE) in the interior of a given region that takes prescribed values on the boundary of the region. The Dirichlet problem can be solved for many PDEs, although originally it was posed for Lap...
https://en.wikipedia.org/wiki/Stratification%20%28mathematics%29
Stratification has several usages in mathematics. In mathematical logic In mathematical logic, stratification is any consistent assignment of numbers to predicate symbols guaranteeing that a unique formal interpretation of a logical theory exists. Specifically, we say that a set of clauses of the form is stratified ...
https://en.wikipedia.org/wiki/Complete%20partial%20order
In mathematics, the phrase complete partial order is variously used to refer to at least three similar, but distinct, classes of partially ordered sets, characterized by particular completeness properties. Complete partial orders play a central role in theoretical computer science: in denotational semantics and domain ...
https://en.wikipedia.org/wiki/Continuity%20correction
In probability theory, a continuity correction is an adjustment that is made when a discrete distribution is approximated by a continuous distribution. Examples Binomial If a random variable X has a binomial distribution with parameters n and p, i.e., X is distributed as the number of "successes" in n independent Be...
https://en.wikipedia.org/wiki/Bell%20polynomials
In combinatorial mathematics, the Bell polynomials, named in honor of Eric Temple Bell, are used in the study of set partitions. They are related to Stirling and Bell numbers. They also occur in many applications, such as in the Faà di Bruno's formula. Definitions Exponential Bell polynomials The partial or incomplet...
https://en.wikipedia.org/wiki/Sphericon
In solid geometry, the sphericon is a solid that has a continuous developable surface with two congruent, semi-circular edges, and four vertices that define a square. It is a member of a special family of rollers that, while being rolled on a flat surface, bring all the points of their surface to contact with the surfa...
https://en.wikipedia.org/wiki/Trapezoidal%20rule
In calculus, the trapezoidal rule (also known as the trapezoid rule or trapezium rule) is a technique for numerical integration, i.e., approximating the definite integral: The trapezoidal rule works by approximating the region under the graph of the function as a trapezoid and calculating its area. It follows that T...
https://en.wikipedia.org/wiki/INSEE%20code
The INSEE code ( ) is a numerical indexing code used by the French National Institute for Statistics and Economic Studies (INSEE) to identify various entities, including communes and départements. They are also used as national identification numbers given to people. Created under Vichy Although today this national i...
https://en.wikipedia.org/wiki/LBB
LBB may stand for: Lactobacillus delbrueckii subsp. bulgaricus, a bacterium used in the production of yogurt Ladyzhenskaya–Babuška–Brezzi condition, in mathematics Laura Bell Bundy, an actress and singer Little brown bird or little brown bats, name given to an unidentified species Little Black Book (disambiguatio...
https://en.wikipedia.org/wiki/Hilbert%20transform
In mathematics and signal processing, the Hilbert transform is a specific singular integral that takes a function, of a real variable and produces another function of a real variable . The Hilbert transform is given by the Cauchy principal value of the convolution with the function (see ). The Hilbert transform ha...
https://en.wikipedia.org/wiki/Cochran%27s%20theorem
In statistics, Cochran's theorem, devised by William G. Cochran, is a theorem used to justify results relating to the probability distributions of statistics that are used in the analysis of variance. Statement Let U1, ..., UN be i.i.d. standard normally distributed random variables, and . Let be symmetric matrices. ...
https://en.wikipedia.org/wiki/Parametric%20equation
In mathematics, a parametric equation defines a group of quantities as functions of one or more independent variables called parameters. Parametric equations are commonly used to express the coordinates of the points that make up a geometric object such as a curve or surface, called a parametric curve and parametric s...
https://en.wikipedia.org/wiki/Nikolai%20Luzin
Nikolai Nikolayevich Luzin (also spelled Lusin; ; 9 December 1883 – 28 February 1950) was a Soviet and Russian mathematician known for his work in descriptive set theory and aspects of mathematical analysis with strong connections to point-set topology. He was the eponym of Luzitania, a loose group of young Moscow math...
https://en.wikipedia.org/wiki/Discriminated%20union
The term discriminated union may refer to: Disjoint union in set theory. Tagged union in computer science. Mathematics disambiguation pages
https://en.wikipedia.org/wiki/Finite%20field%20arithmetic
In mathematics, finite field arithmetic is arithmetic in a finite field (a field containing a finite number of elements) contrary to arithmetic in a field with an infinite number of elements, like the field of rational numbers. There are infinitely many different finite fields. Their number of elements is necessarily ...
https://en.wikipedia.org/wiki/Congruence%20of%20squares
In number theory, a congruence of squares is a congruence commonly used in integer factorization algorithms. Derivation Given a positive integer n, Fermat's factorization method relies on finding numbers x and y satisfying the equality We can then factor n = x2 − y2 = (x + y)(x − y). This algorithm is slow in practic...
https://en.wikipedia.org/wiki/Decision%20tree%20learning
Decision tree learning is a supervised learning approach used in statistics, data mining and machine learning. In this formalism, a classification or regression decision tree is used as a predictive model to draw conclusions about a set of observations. Tree models where the target variable can take a discrete set of ...
https://en.wikipedia.org/wiki/Magnitude%20%28mathematics%29
In mathematics, the magnitude or size of a mathematical object is a property which determines whether the object is larger or smaller than other objects of the same kind. More formally, an object's magnitude is the displayed result of an ordering (or ranking) of the class of objects to which it belongs. In physics, ma...
https://en.wikipedia.org/wiki/Banach%E2%80%93Alaoglu%20theorem
In functional analysis and related branches of mathematics, the Banach–Alaoglu theorem (also known as Alaoglu's theorem) states that the closed unit ball of the dual space of a normed vector space is compact in the weak* topology. A common proof identifies the unit ball with the weak-* topology as a closed subset of a...
https://en.wikipedia.org/wiki/Compact%20operator
In functional analysis, a branch of mathematics, a compact operator is a linear operator , where are normed vector spaces, with the property that maps bounded subsets of to relatively compact subsets of (subsets with compact closure in ). Such an operator is necessarily a bounded operator, and so continuous. Some a...
https://en.wikipedia.org/wiki/Simple%20algebra%20%28universal%20algebra%29
In universal algebra, an abstract algebra A is called simple if and only if it has no nontrivial congruence relations, or equivalently, if every homomorphism with domain A is either injective or constant. As congruences on rings are characterized by their ideals, this notion is a straightforward generalization of th...
https://en.wikipedia.org/wiki/James%20Alan%20Gardner
James Alan Gardner (born January 10, 1955) is a Canadian science fiction author. Raised in Simcoe and Bradford, Ontario, he earned bachelor's and master's degrees in applied mathematics from the University of Waterloo. Gardner has published science fiction short stories in a range of periodicals, including The Magazi...
https://en.wikipedia.org/wiki/Scott%20Vanstone
Scott A. Vanstone was a mathematician and cryptographer in the University of Waterloo Faculty of Mathematics. He was a member of the school's Centre for Applied Cryptographic Research, and was also a founder of the cybersecurity company Certicom. He received his PhD in 1974 at the University of Waterloo, and for abou...
https://en.wikipedia.org/wiki/Additive
Additive may refer to: Mathematics Additive function, a function in number theory Additive map, a function that preserves the addition operation Additive set-function see Sigma additivity Additive category, a preadditive category with finite biproducts Additive inverse, an arithmetic concept Science Additive co...
https://en.wikipedia.org/wiki/Scholz%20conjecture
In mathematics, the Scholz conjecture is a conjecture on the length of certain addition chains. It is sometimes also called the Scholz–Brauer conjecture or the Brauer–Scholz conjecture, after Arnold Scholz who formulated it in 1937 and Alfred Brauer who studied it soon afterward and proved a weaker bound. Statement Th...
https://en.wikipedia.org/wiki/Addition%20chain
In mathematics, an addition chain for computing a positive integer can be given by a sequence of natural numbers starting with 1 and ending with , such that each number in the sequence is the sum of two previous numbers. The length of an addition chain is the number of sums needed to express all its numbers, which is ...
https://en.wikipedia.org/wiki/Image%20%28mathematics%29
In mathematics, the image of a function is the set of all output values it may produce. More generally, evaluating a given function at each element of a given subset of its domain produces a set, called the "image of under (or through) ". Similarly, the inverse image (or preimage) of a given subset of the codomain...
https://en.wikipedia.org/wiki/Curve%20of%20constant%20width
In geometry, a curve of constant width is a simple closed curve in the plane whose width (the distance between parallel supporting lines) is the same in all directions. The shape bounded by a curve of constant width is a body of constant width or an orbiform, the name given to these shapes by Leonhard Euler. Standard e...
https://en.wikipedia.org/wiki/Barbier%27s%20theorem
In geometry, Barbier's theorem states that every curve of constant width has perimeter times its width, regardless of its precise shape. This theorem was first published by Joseph-Émile Barbier in 1860. Examples The most familiar examples of curves of constant width are the circle and the Reuleaux triangle. For a c...
https://en.wikipedia.org/wiki/Hopf%20fibration
In the mathematical field of differential topology, the Hopf fibration (also known as the Hopf bundle or Hopf map) describes a 3-sphere (a hypersphere in four-dimensional space) in terms of circles and an ordinary sphere. Discovered by Heinz Hopf in 1931, it is an influential early example of a fiber bundle. Technicall...
https://en.wikipedia.org/wiki/Implicit%20function%20theorem
In multivariable calculus, the implicit function theorem is a tool that allows relations to be converted to functions of several real variables. It does so by representing the relation as the graph of a function. There may not be a single function whose graph can represent the entire relation, but there may be such a f...
https://en.wikipedia.org/wiki/Plus%20construction
In mathematics, the plus construction is a method for simplifying the fundamental group of a space without changing its homology and cohomology groups. Explicitly, if is a based connected CW complex and is a perfect normal subgroup of then a map is called a +-construction relative to if induces an isomorphism o...
https://en.wikipedia.org/wiki/Cram%C3%A9r%E2%80%93Rao%20bound
In estimation theory and statistics, the Cramér–Rao bound (CRB) relates to estimation of a deterministic (fixed, though unknown) parameter. The result is named in honor of Harald Cramér and C. R. Rao, but has also been derived independently by Maurice Fréchet, Georges Darmois, and by Alexander Aitken and Harold Silver...
https://en.wikipedia.org/wiki/Isogonal%20figure
In geometry, a polytope (e.g. a polygon or polyhedron) or a tiling is isogonal or vertex-transitive if all its vertices are equivalent under the symmetries of the figure. This implies that each vertex is surrounded by the same kinds of face in the same or reverse order, and with the same angles between corresponding f...
https://en.wikipedia.org/wiki/Kummer%20theory
In abstract algebra and number theory, Kummer theory provides a description of certain types of field extensions involving the adjunction of nth roots of elements of the base field. The theory was originally developed by Ernst Eduard Kummer around the 1840s in his pioneering work on Fermat's Last Theorem. The main stat...
https://en.wikipedia.org/wiki/Singularity%20theory
In mathematics, singularity theory studies spaces that are almost manifolds, but not quite. A string can serve as an example of a one-dimensional manifold, if one neglects its thickness. A singularity can be made by balling it up, dropping it on the floor, and flattening it. In some places the flat string will cross it...
https://en.wikipedia.org/wiki/Real%20field
Real field may refer to: Real numbers, the numbers that can be represented by infinite decimals Formally real field, an algebraic field that has the so-called "real" property Real closed field Real quadratic field
https://en.wikipedia.org/wiki/Invertible%20sheaf
In mathematics, an invertible sheaf is a sheaf on a ringed space which has an inverse with respect to tensor product of sheaves of modules. It is the equivalent in algebraic geometry of the topological notion of a line bundle. Due to their interactions with Cartier divisors, they play a central role in the study of alg...
https://en.wikipedia.org/wiki/Pushout%20%28category%20theory%29
In category theory, a branch of mathematics, a pushout (also called a fibered coproduct or fibered sum or cocartesian square or amalgamated sum) is the colimit of a diagram consisting of two morphisms f : Z → X and g : Z → Y with a common domain. The pushout consists of an object P along with two morphisms X → P and Y...
https://en.wikipedia.org/wiki/Lefschetz%20fixed-point%20theorem
In mathematics, the Lefschetz fixed-point theorem is a formula that counts the fixed points of a continuous mapping from a compact topological space to itself by means of traces of the induced mappings on the homology groups of . It is named after Solomon Lefschetz, who first stated it in 1926. The counting is subje...
https://en.wikipedia.org/wiki/Theory%20of%20equations
In algebra, the theory of equations is the study of algebraic equations (also called "polynomial equations"), which are equations defined by a polynomial. The main problem of the theory of equations was to know when an algebraic equation has an algebraic solution. This problem was completely solved in 1830 by Évariste ...
https://en.wikipedia.org/wiki/Simplicial%20approximation%20theorem
In mathematics, the simplicial approximation theorem is a foundational result for algebraic topology, guaranteeing that continuous mappings can be (by a slight deformation) approximated by ones that are piecewise of the simplest kind. It applies to mappings between spaces that are built up from simplices—that is, finit...
https://en.wikipedia.org/wiki/Barycentric%20subdivision
In mathematics, the barycentric subdivision is a standard way to subdivide a given simplex into smaller ones. Its extension on simplicial complexes is a canonical method to refine them. Therefore, the barycentric subdivision is an important tool in algebraic topology. Motivation The barycentric subdivision is an oper...
https://en.wikipedia.org/wiki/Tarski%27s%20undefinability%20theorem
Tarski's undefinability theorem, stated and proved by Alfred Tarski in 1933, is an important limitative result in mathematical logic, the foundations of mathematics, and in formal semantics. Informally, the theorem states that "arithmetical truth cannot be defined in arithmetic". The theorem applies more generally to ...
https://en.wikipedia.org/wiki/Topological%20abelian%20group
In mathematics, a topological abelian group, or TAG, is a topological group that is also an abelian group. That is, a TAG is both a group and a topological space, the group operations are continuous, and the group's binary operation is commutative. The theory of topological groups applies also to TAGs, but more can be...
https://en.wikipedia.org/wiki/Octahedral%20number
In number theory, an octahedral number is a figurate number that represents the number of spheres in an octahedron formed from close-packed spheres. The octahedral number can be obtained by the formula: The first few octahedral numbers are: 1, 6, 19, 44, 85, 146, 231, 344, 489, 670, 891 . Properties and applicati...
https://en.wikipedia.org/wiki/Scaling
Scaling may refer to: Science and technology Mathematics and physics Scaling (geometry), a linear transformation that enlarges or diminishes objects Scale invariance, a feature of objects or laws that do not change if scales of length, energy, or other variables are multiplied by a common factor Scaling law, a law...
https://en.wikipedia.org/wiki/Closed-form%20expression
In mathematics, an expression is in closed form if it is formed with constants, variables and a finite set of basic functions connected by arithmetic operations (, and integer powers) and function composition. Commonly, the allowed functions are nth root, exponential function, logarithm, and trigonometric functions . H...
https://en.wikipedia.org/wiki/Perfect%20group
In mathematics, more specifically in group theory, a group is said to be perfect if it equals its own commutator subgroup, or equivalently, if the group has no non-trivial abelian quotients (equivalently, its abelianization, which is the universal abelian quotient, is trivial). In symbols, a perfect group is one such t...
https://en.wikipedia.org/wiki/Homology%20sphere
In algebraic topology, a homology sphere is an n-manifold X having the homology groups of an n-sphere, for some integer . That is, and for all other i. Therefore X is a connected space, with one non-zero higher Betti number, namely, . It does not follow that X is simply connected, only that its fundamental grou...
https://en.wikipedia.org/wiki/NUTS%20statistical%20regions%20of%20Sweden
In the NUTS (Nomenclature of Territorial Units for Statistics) codes of Sweden (SE), the three levels are: NUTS codes SE SWEDEN (SVERIGE) SE1 EAST SWEDEN (ÖSTRA SVERIGE) SE11 Stockholm (Stockholm) SE110 Stockholm County (Stockholms län) SE12 East Middle Sweden (Östra Mellansverige) SE121 Uppsala County (Uppsala län) ...
https://en.wikipedia.org/wiki/Integer-valued%20polynomial
In mathematics, an integer-valued polynomial (also known as a numerical polynomial) is a polynomial whose value is an integer for every integer n. Every polynomial with integer coefficients is integer-valued, but the converse is not true. For example, the polynomial takes on integer values whenever t is an integer. ...
https://en.wikipedia.org/wiki/Invariant%20subspace
In mathematics, an invariant subspace of a linear mapping T : V → V i.e. from some vector space V to itself, is a subspace W of V that is preserved by T. More generally, an invariant subspace for a collection of linear mappings is a subspace preserved by each mapping individually. For a single operator Consider a v...
https://en.wikipedia.org/wiki/List%20of%20NHL%20statistical%20leaders
Skaters The statistics listed include the 2022–23 NHL regular season and 2023 playoffs. All-time leaders (skaters) Active skaters (during 2023–24 NHL season) are listed in boldface. Regular season: Points Regular season: Points per game Minimum 500 points Wayne Gretzky, 1.921 Mario Lemieux, 1.883 Mike Bossy,...
https://en.wikipedia.org/wiki/Complementarity
Complementarity may refer to: Physical sciences and mathematics Complementarity (molecular biology), a property of nucleic acid molecules in molecular biology Complementarity (physics), the principle that objects have complementary properties which cannot all be observed or measured simultaneously Complementarity t...
https://en.wikipedia.org/wiki/Dictionary%20order
Dictionary order may refer to: Alphabetical order § Treatment of multiword strings Other collation systems used to order words in dictionaries Lexicographic order in mathematics
https://en.wikipedia.org/wiki/Signed%20number%20representations
In computing, signed number representations are required to encode negative numbers in binary number systems. In mathematics, negative numbers in any base are represented by prefixing them with a minus sign ("−"). However, in RAM or CPU registers, numbers are represented only as sequences of bits, without extra symbol...
https://en.wikipedia.org/wiki/Pursuit%20curve
In geometry, a curve of pursuit is a curve constructed by analogy to having a point or points representing pursuers and pursuees; the curve of pursuit is the curve traced by the pursuers. With the paths of the pursuer and pursuee parameterized in time, the pursuee is always on the pursuer's tangent. That is, given , t...
https://en.wikipedia.org/wiki/Nerve%20complex
In topology, the nerve complex of a set family is an abstract complex that records the pattern of intersections between the sets in the family. It was introduced by Pavel Alexandrov and now has many variants and generalisations, among them the Čech nerve of a cover, which in turn is generalised by hypercoverings. It ca...
https://en.wikipedia.org/wiki/Kakeya%20set
In mathematics, a Kakeya set, or Besicovitch set, is a set of points in Euclidean space which contains a unit line segment in every direction. For instance, a disk of radius 1/2 in the Euclidean plane, or a ball of radius 1/2 in three-dimensional space, forms a Kakeya set. Much of the research in this area has studied ...
https://en.wikipedia.org/wiki/Borel%20subgroup
In the theory of algebraic groups, a Borel subgroup of an algebraic group G is a maximal Zariski closed and connected solvable algebraic subgroup. For example, in the general linear group GLn (n x n invertible matrices), the subgroup of invertible upper triangular matrices is a Borel subgroup. For groups realized over...
https://en.wikipedia.org/wiki/John%20Winthrop%20%28educator%29
John Winthrop (December 19, 1714 – May 3, 1779) was an American mathematician, physicist and astronomer. He was the 2nd Hollis Professor of Mathematics and Natural Philosophy in Harvard College. Early life John Winthrop was born in Boston, Massachusetts. His great-great-grandfather, also named John Winthrop, was found...
https://en.wikipedia.org/wiki/Kurt%20Hirsch
Kurt August Hirsch (12 January 1906 – 4 November 1986) was a German mathematician who moved to England to escape the Nazi persecution of Jews. His research was in group theory. He also worked to reform mathematics education and became a county chess champion. The Hirsch length and Hirsch–Plotkin radical are named after...
https://en.wikipedia.org/wiki/Special%20number%20field%20sieve
In number theory, a branch of mathematics, the special number field sieve (SNFS) is a special-purpose integer factorization algorithm. The general number field sieve (GNFS) was derived from it. The special number field sieve is efficient for integers of the form re ± s, where r and s are small (for instance Mersenne n...
https://en.wikipedia.org/wiki/Frank%20Morley
Frank Morley (September 9, 1860 – October 17, 1937) was a leading mathematician, known mostly for his teaching and research in the fields of algebra and geometry. Among his mathematical accomplishments was the discovery and proof of the celebrated Morley's trisector theorem in elementary plane geometry. He led 50 Ph.D....
https://en.wikipedia.org/wiki/George%20Salmon
George Salmon FBA FRS FRSE (25 September 1819 – 22 January 1904) was a distinguished and influential Irish mathematician and Anglican theologian. After working in algebraic geometry for two decades, Salmon devoted the last forty years of his life to theology. His entire career was spent at Trinity College Dublin. Pers...
https://en.wikipedia.org/wiki/Norman%20Steenrod
Norman Earl Steenrod (April 22, 1910October 14, 1971) was an American mathematician most widely known for his contributions to the field of algebraic topology. Life He was born in Dayton, Ohio, and educated at Miami University and University of Michigan (A.B. 1932). After receiving a master's degree from Harvard Unive...
https://en.wikipedia.org/wiki/Perxenate
In chemistry, perxenates are salts of the yellow xenon-containing anion . This anion has octahedral molecular geometry, as determined by Raman spectroscopy, having O–Xe–O bond angles varying between 87° and 93°. The Xe–O bond length was determined by X-ray crystallography to be 1.875 Å. Synthesis Perxenates are synt...
https://en.wikipedia.org/wiki/Strong%20topology
In mathematics, a strong topology is a topology which is stronger than some other "default" topology. This term is used to describe different topologies depending on context, and it may refer to: the final topology on the disjoint union the topology arising from a norm the strong operator topology the strong topol...
https://en.wikipedia.org/wiki/Isotopic
Isotopic may refer to: In the physical sciences, to do with chemical isotopes In mathematics, to do with a relation called isotopy; see Isotopy (disambiguation) In geometry, isotopic refers to facet-transitivity
https://en.wikipedia.org/wiki/Nicolaus%20Rohlfs
Nicolaus Rohlfs was an 18th-century German mathematics teacher (arithmeticus) in Buxtehude and Hamburg who wrote astronomical calendars, a book about gardening, and other treatises that were continued by Matthias Rohlfs. Works Trigonometrische Calculation, der Anno Christi 1724. den 22 Maji ... vorfallenden grossen...
https://en.wikipedia.org/wiki/Path%20analysis%20%28statistics%29
In statistics, path analysis is used to describe the directed dependencies among a set of variables. This includes models equivalent to any form of multiple regression analysis, factor analysis, canonical correlation analysis, discriminant analysis, as well as more general families of models in the multivariate analysi...
https://en.wikipedia.org/wiki/London%20Mathematical%20Society
The London Mathematical Society (LMS) is one of the United Kingdom's learned societies for mathematics (the others being the Royal Statistical Society (RSS), the Institute of Mathematics and its Applications (IMA), the Edinburgh Mathematical Society and the Operational Research Society (ORS). History The Society was e...
https://en.wikipedia.org/wiki/Willem%20de%20Sitter
Willem de Sitter (6 May 1872 – 20 November 1934) was a Dutch mathematician, physicist, and astronomer. Life and work Born in Sneek, de Sitter studied mathematics at the University of Groningen and then joined the Groningen astronomical laboratory. He worked at the Cape Observatory in South Africa (1897–1899). Then, in...
https://en.wikipedia.org/wiki/Hurewicz%20theorem
In mathematics, the Hurewicz theorem is a basic result of algebraic topology, connecting homotopy theory with homology theory via a map known as the Hurewicz homomorphism. The theorem is named after Witold Hurewicz, and generalizes earlier results of Henri Poincaré. Statement of the theorems The Hurewicz theorems are ...
https://en.wikipedia.org/wiki/Even%20and%20odd%20functions
In mathematics, even functions and odd functions are functions which satisfy particular symmetry relations, with respect to taking additive inverses. They are important in many areas of mathematical analysis, especially the theory of power series and Fourier series. They are named for the parity of the powers of the po...
https://en.wikipedia.org/wiki/Current%20Population%20Survey
The Current Population Survey (CPS) is a monthly survey of about 60,000 U.S. households conducted by the United States Census Bureau for the Bureau of Labor Statistics (BLS). The BLS uses the data to publish reports early each month called the Employment Situation. This report provides estimates of the unemployment rat...
https://en.wikipedia.org/wiki/Hypocycloid
In geometry, a hypocycloid is a special plane curve generated by the trace of a fixed point on a small circle that rolls within a larger circle. As the radius of the larger circle is increased, the hypocycloid becomes more like the cycloid created by rolling a circle on a line. History The 2-cusped hypocycloid called ...
https://en.wikipedia.org/wiki/Hellinger%E2%80%93Toeplitz%20theorem
In functional analysis, a branch of mathematics, the Hellinger–Toeplitz theorem states that an everywhere-defined symmetric operator on a Hilbert space with inner product is bounded. By definition, an operator A is symmetric if for all x, y in the domain of A. Note that symmetric everywhere-defined operators are ne...
https://en.wikipedia.org/wiki/Liisi%20Oterma
Liisi Oterma (; 6 January 1915 – 4 April 2001) was a Finnish astronomer, the first woman to get a Ph.D. degree in astronomy in Finland. She studied mathematics and astronomy at the University of Turku, and soon became Yrjö Väisälä's assistant and worked on the search for minor planets. She obtained her master's degre...
https://en.wikipedia.org/wiki/Point%20%28geometry%29
In classical Euclidean geometry, a point is a primitive notion that models an exact location in space, and has no length, width, or thickness. In modern mathematics, a point is considered as an element of some set, a point set. A space is a point set with some additional structure. An isolated point has no other neighb...
https://en.wikipedia.org/wiki/Unimodular%20matrix
In mathematics, a unimodular matrix M is a square integer matrix having determinant +1 or −1. Equivalently, it is an integer matrix that is invertible over the integers: there is an integer matrix N that is its inverse (these are equivalent under Cramer's rule). Thus every equation , where M and b both have integer com...
https://en.wikipedia.org/wiki/Indeterminate
Indeterminate may refer to: In mathematics Indeterminate (variable), a symbol that is treated as a variable Indeterminate system, a system of simultaneous equations that has more than one solution Indeterminate equation, an equation that has more than one solution Indeterminate form, an algebraic expression with c...
https://en.wikipedia.org/wiki/NUTS%20statistical%20regions%20of%20Finland
In the NUTS (Nomenclature of Territorial Units for Statistics) codes of Finland (FI), the three levels are: NUTS codes 2013 version. In the 2003 version, Satakunta was coded FI191, and Pirkanmaa was coded FI192. Local administrative units Below the NUTS levels, the two LAU (Local Administrative Units) levels are: ...
https://en.wikipedia.org/wiki/Propagation%20of%20uncertainty
In statistics, propagation of uncertainty (or propagation of error) is the effect of variables' uncertainties (or errors, more specifically random errors) on the uncertainty of a function based on them. When the variables are the values of experimental measurements they have uncertainties due to measurement limitations...
https://en.wikipedia.org/wiki/NUTS%20statistical%20regions%20of%20Denmark
The Nomenclature of Territorial Units for Statistics (NUTS) is a geocode standard for referencing the administrative division of Denmark for statistical purposes. The standard is developed and regulated by the European Union. The NUTS standard is instrumental in delivering the European Union's Structural Funds. The NUT...
https://en.wikipedia.org/wiki/QR%20algorithm
In numerical linear algebra, the QR algorithm or QR iteration is an eigenvalue algorithm: that is, a procedure to calculate the eigenvalues and eigenvectors of a matrix. The QR algorithm was developed in the late 1950s by John G. F. Francis and by Vera N. Kublanovskaya, working independently. The basic idea is to perf...
https://en.wikipedia.org/wiki/Lucas%20chain
In mathematics, a Lucas chain is a restricted type of addition chain, named for the French mathematician Édouard Lucas. It is a sequence a0, a1, a2, a3, ... that satisfies a0=1, and for each k > 0: ak = ai + aj, and either ai = aj or |ai − aj| = am, for some i, j, m < k. The sequence of powers of 2 (1, 2, 4, 8...
https://en.wikipedia.org/wiki/Compactly%20generated%20group
In mathematics, a compactly generated (topological) group is a topological group G which is algebraically generated by one of its compact subsets. This should not be confused with the unrelated notion (widely used in algebraic topology) of a compactly generated space -- one whose topology is generated (in a suitable se...
https://en.wikipedia.org/wiki/Compactly%20generated
In mathematics, compactly generated can refer to: Compactly generated group, a topological group which is algebraically generated by one of its compact subsets Compactly generated space, a topological space whose topology is coherent with the family of all compact subspaces Mathematics disambiguation pages
https://en.wikipedia.org/wiki/John%20Allen%20Paulos
John Allen Paulos (born July 4, 1945) is an American professor of mathematics at Temple University in Philadelphia, Pennsylvania. He has gained fame as a writer and speaker on mathematics and the importance of mathematical literacy. Paulos writes about many subjects, especially of the dangers of mathematical innumeracy...
https://en.wikipedia.org/wiki/Functional%20equation%20%28L-function%29
In mathematics, the L-functions of number theory are expected to have several characteristic properties, one of which is that they satisfy certain functional equations. There is an elaborate theory of what these equations should be, much of which is still conjectural. Introduction A prototypical example, the Riemann...
https://en.wikipedia.org/wiki/Tschirnhaus%20transformation
In mathematics, a Tschirnhaus transformation, also known as Tschirnhausen transformation, is a type of mapping on polynomials developed by Ehrenfried Walther von Tschirnhaus in 1683. Simply, it is a method for transforming a polynomial equation of degree with some nonzero intermediate coefficients, , such that some o...
https://en.wikipedia.org/wiki/Chowla%E2%80%93Mordell%20theorem
In mathematics, the Chowla–Mordell theorem is a result in number theory determining cases where a Gauss sum is the square root of a prime number, multiplied by a root of unity. It was proved and published independently by Sarvadaman Chowla and Louis Mordell, around 1951. In detail, if is a prime number, a nontrivial...
https://en.wikipedia.org/wiki/Quadratic%20Gauss%20sum
In number theory, quadratic Gauss sums are certain finite sums of roots of unity. A quadratic Gauss sum can be interpreted as a linear combination of the values of the complex exponential function with coefficients given by a quadratic character; for a general character, one obtains a more general Gauss sum. These obje...
https://en.wikipedia.org/wiki/Chowla%E2%80%93Selberg%20formula
In mathematics, the Chowla–Selberg formula is the evaluation of a certain product of values of the gamma function at rational values in terms of values of the Dedekind eta function at imaginary quadratic irrational numbers. The result was essentially found by and rediscovered by . Statement In logarithmic form, the ...