question_id
int64
25.6k
509k
title
stringlengths
27
150
link
stringlengths
67
130
score
int64
0
73
view_count
int64
13
44k
answer_count
int64
0
43
is_answered
bool
2 classes
has_accepted_answer
bool
2 classes
accepted_answer_id
int64
61.8k
509k
tags
stringlengths
8
106
creation_date
stringdate
2026-03-04 05:32:13
2026-03-05 10:24:18
last_activity_date
stringclasses
1 value
body_html
stringlengths
0
6.26k
comments
listlengths
0
5
answers
listlengths
0
30
508,744
Possible numbers of integer points that an $n$-by-$n$ square can cover
https://mathoverflow.net/questions/508744/possible-numbers-of-integer-points-that-an-n-by-n-square-can-cover
2
60
1
true
false
null
discrete-geometry
2026-03-05 10:24:18Z
<div class="s-prose js-post-body" itemprop="text"> <p>For positive integer <span class="math-container">$n$</span>, how many integer points can an <span class="math-container">$n$</span>-by-<span class="math-container">$n$</span> square in the plane possibly cover?</p> <p>Let <span class="math-container">$E$</span> be ...
[ { "author_id": 552730, "author_name": "Oleg Orlov", "author_url": "https://mathoverflow.net/users/552730/oleg-orlov", "body_html": "<span class=\"comment-copy\" itemprop=\"text\">A square can cover less than $n^2$ integer points, e. g. for $n=1$ the tilted square with center $(0.5,0.5)$ doesn't cove...
[ { "answer_id": 508778, "author_id": 586494, "author_name": "Elias Panholzer", "author_reputation": 140, "author_url": "https://mathoverflow.net/users/586494/elias-panholzer", "body_html": "<div class=\"s-prose js-post-body\" itemprop=\"text\">\n<p>Case 1: all 4 sides cover integer points: By...
508,767
Capping off an almost complex structure over a cone on a link of a quotient surface singularity
https://mathoverflow.net/questions/508767/capping-off-an-almost-complex-structure-over-a-cone-on-a-link-of-a-quotient-surf
1
48
0
false
false
null
dg.differential-geometry;4-manifolds;orbifolds
2026-03-05 10:05:53Z
<div class="s-prose js-post-body" itemprop="text"> <p>Let <span class="math-container">$Y$</span> be an oriented <span class="math-container">$3$</span>-dimesional manifold, given by a link of a surface quotient singularity. This means that <span class="math-container">$Y=S^3/G$</span> for some finite subgroup <span cl...
[ { "author_id": 13061, "author_name": "Johannes Nordström", "author_url": "https://mathoverflow.net/users/13061/johannes-nordstr%c3%b6m", "body_html": "<span class=\"comment-copy\" itemprop=\"text\">You say \"orbifold\", but you seem initially to not impose any conditions on Y that ensure that CY is ...
[]
508,689
Nonlinear wave equation and the light cone
https://mathoverflow.net/questions/508689/nonlinear-wave-equation-and-the-light-cone
0
113
0
false
false
null
reference-request;ap.analysis-of-pdes;wave-equation
2026-03-04 18:53:20Z
<div class="s-prose js-post-body" itemprop="text"> <p>I have a basic question about the nonlinear wave equation. I am looking to prove the existence of a self similar solution to a wave equation; say <span class="math-container">$u=u(x,t)$</span> <span class="math-container">$$ u_{tt}-\Delta_x u = |u|^{p-2} u$$</spa...
[ { "author_id": 586494, "author_name": "Elias Panholzer", "author_url": "https://mathoverflow.net/users/586494/elias-panholzer", "body_html": "<span class=\"comment-copy\" itemprop=\"text\">Vladimir Georgiev and Grozdena Todorova. \"Existence of a Solution of the Wave Equation with Nonlinear Damping ...
[]
508,160
Counterexamples in Simon-Smith min-max theory
https://mathoverflow.net/questions/508160/counterexamples-in-simon-smith-min-max-theory
1
88
1
true
false
null
riemannian-geometry;geometric-measure-theory;minimal-surfaces
2026-03-04 18:48:46Z
<div class="s-prose js-post-body" itemprop="text"> <p>I am reading about the Simon-Smith min-max method for constructing minimal surfaces in 3-manifolds, following <a href="https://www.math.ias.edu/delellis/sites/math.ias.edu.delellis/files/MinMax92.pdf" rel="nofollow noreferrer">this survey</a> by Colding and De Lelli...
[]
[ { "answer_id": 508753, "author_id": 1540, "author_name": "Otis Chodosh", "author_reputation": 7412, "author_url": "https://mathoverflow.net/users/1540/otis-chodosh", "body_html": "<div class=\"s-prose js-post-body\" itemprop=\"text\">\n<p>Take <span class=\"math-container\">$S^3(\\sqrt{2})\\...
508,721
Is the set of all hypergeometric identities finitely generated?
https://mathoverflow.net/questions/508721/is-the-set-of-all-hypergeometric-identities-finitely-generated
8
352
2
true
false
null
hypergeometric-functions
2026-03-04 18:33:07Z
<div class="s-prose js-post-body" itemprop="text"> <p>If we look at Wikipedia's <a href="https://en.wikipedia.org/wiki/Generalized_hypergeometric_function#Identities" rel="noreferrer">list of hypergeometric identities</a>, we find classic results such as Saalschütz's theorem— <span class="math-container">$${}_3F_2 (a,b...
[ { "author_id": 7092, "author_name": "Steven Stadnicki", "author_url": "https://mathoverflow.net/users/7092/steven-stadnicki", "body_html": "<span class=\"comment-copy\" itemprop=\"text\">Would all the sorts of things you're thinking about be covered by W-Z pairs? <a href=\"https://en.wikipedia.org/w...
[ { "answer_id": 508745, "author_id": 3106, "author_name": "Timothy Chow", "author_reputation": 91241, "author_url": "https://mathoverflow.net/users/3106/timothy-chow", "body_html": "<div class=\"s-prose js-post-body\" itemprop=\"text\">\n<p>I did what I should have done before posting to MO, ...
61,773
$p$-adic Langlands correspondence
https://mathoverflow.net/questions/61773/p-adic-langlands-correspondence
23
3,000
2
true
true
61,808
reference-request;nt.number-theory;galois-representations
2026-03-04 18:00:02Z
<div class="s-prose js-post-body" itemprop="text"> <p>Basic question: Is it correct that the $p$-adic Langlands correspondence is known for $GL_2$ only over $Q_p$ but not other $p$-adic fields? If so, I would like to request some light to be shed on this restriction, i.e., why only $Q_p$ but not its extensions. Any ref...
[ { "author_id": 2821, "author_name": "Chandan Singh Dalawat", "author_url": "https://mathoverflow.net/users/2821/chandan-singh-dalawat", "body_html": "<span class=\"comment-copy\" itemprop=\"text\">Start with Pierre Berger's recent Bourbaki exposé 1017 <a href=\"http://arxiv.org/abs/1002.4111\" rel=\...
[ { "answer_id": 61808, "author_id": 13024, "author_name": "vytas", "author_reputation": 433, "author_url": "https://mathoverflow.net/users/13024/vytas", "body_html": "<div class=\"s-prose js-post-body\" itemprop=\"text\">\n<p>Yes, this is correct.</p>\n<p>The problem is that when you replace ...
488,840
Binomial coefficient C(2k,n-1) alternative formula equivalent to the Vandermonde identity?
https://mathoverflow.net/questions/488840/binomial-coefficient-c2k-n-1-alternative-formula-equivalent-to-the-vandermonde
1
467
3
true
true
488,880
reference-request;co.combinatorics;linear-algebra;binomial-coefficients;recurrences
2026-03-04 17:31:53Z
<div class="s-prose js-post-body" itemprop="text"> <p>I am working with a binomial sum that arises in some combinatorial arguments (and also appears in certain generating‐function manipulations). Specifically, I have this identity</p> <p><span class="math-container">$$ \sum_{j=0}^{n} \binom{k}{j}\,\binom{k}{n-j} \;=\; ...
[ { "author_id": 7076, "author_name": "Max Alekseyev", "author_url": "https://mathoverflow.net/users/7076/max-alekseyev", "body_html": "<span class=\"comment-copy\" itemprop=\"text\">Why is it important to link the two sums rather than link the second sum directly to the binomial coefficient $\\binom{...
[ { "answer_id": 488880, "author_id": 10744, "author_name": "Ira Gessel", "author_reputation": 17728, "author_url": "https://mathoverflow.net/users/10744/ira-gessel", "body_html": "<div class=\"s-prose js-post-body\" itemprop=\"text\">\n<p>The identity is a special case of <a href=\"https://en...
472,830
Show that $\|P(f\circ\varphi_{\lambda})-\widetilde{f}(\lambda)\|_p=\|P(f\circ\varphi_{\lambda}-\overline{P(\overline{f}\circ\varphi_{\lambda}}))\|_p.$
https://mathoverflow.net/questions/472830/show-that-pf-circ-varphi-lambda-widetildef-lambda-p-pf-circ-va
2
316
1
true
false
null
fa.functional-analysis;measure-theory;operator-theory;function-spaces;toeplitz-operators
2026-03-04 17:11:15Z
<div class="s-prose js-post-body" itemprop="text"> <p>Let <span class="math-container">$\Omega = \mathbb B_n,$</span> the unit ball in <span class="math-container">$\mathbb C^n$</span> and <span class="math-container">$L^2_a(\Omega)$</span> be the Bergman space endowed with the normalized volume measure on <span class=...
[]
[ { "answer_id": 473110, "author_id": 153260, "author_name": "an_ordinary_mathematician", "author_reputation": 3226, "author_url": "https://mathoverflow.net/users/153260/an-ordinary-mathematician", "body_html": "<div class=\"s-prose js-post-body\" itemprop=\"text\">\n<p>I think it goes like th...
195,938
Grothendieck on polyhedra over finite fields
https://mathoverflow.net/questions/195938/grothendieck-on-polyhedra-over-finite-fields
26
1,000
1
true
false
null
reference-request;co.combinatorics;ho.history-overview;discrete-geometry;finite-fields
2026-03-04 16:04:28Z
<div class="s-prose js-post-body" itemprop="text"> <p>In Grothendieck's <em>Sketch of a Programme</em> he spends a few pages discussing polyhedra over arbitrary rings and concludes with some intriguing remarks on specializing polyhedra over their "most singular characteristics". I am having trouble understanding what h...
[ { "author_id": 50846, "author_name": "Matthias Wendt", "author_url": "https://mathoverflow.net/users/50846/matthias-wendt", "body_html": "<span class=\"comment-copy\" itemprop=\"text\">Could the singular characteristic have something to do with the modular representation theory of the automorphism g...
[ { "answer_id": 423573, "author_id": 429204, "author_name": "user234212323", "author_reputation": 934, "author_url": "https://mathoverflow.net/users/429204/user234212323", "body_html": "<div class=\"s-prose js-post-body\" itemprop=\"text\">\n<p>Not an exact answer to your question but maybe i...
488,866
Generalization of Chebyshev polynomials with connection to K-bonacci sequence number
https://mathoverflow.net/questions/488866/generalization-of-chebyshev-polynomials-with-connection-to-k-bonacci-sequence-nu
3
183
1
true
true
508,749
co.combinatorics;computability-theory;binomial-coefficients;recurrences;trigonometric-polynomials
2026-03-04 15:49:13Z
<div class="s-prose js-post-body" itemprop="text"> <p>I have been exploring a combinatorial approach to express Chebyshev polynomials and generalizing them through a recurrence relation. I would like to know whether this recurrence relation can be proven using induction or a combinatorial approach.</p> <p><span class="...
[ { "author_id": 2530, "author_name": "darij grinberg", "author_url": "https://mathoverflow.net/users/2530/darij-grinberg", "body_html": "<span class=\"comment-copy\" itemprop=\"text\">Without getting into anything deep, a few comments: Have you seen the work of Arthur Benjamin and others, e.g., <a hr...
[ { "answer_id": 508749, "author_id": null, "author_name": "TigranNersissian", "author_reputation": 1, "author_url": "", "body_html": "<div class=\"s-prose js-post-body\" itemprop=\"text\">\n<p><b>Proof.</b> <i>Given the generalized Chebyshev polynomial:</i>\n<span class=\"math-container\">$$G...
508,702
Intuitive explanation why the radii converge in this sequence of eights?
https://mathoverflow.net/questions/508702/intuitive-explanation-why-the-radii-converge-in-this-sequence-of-eights
19
1,000
4
true
true
508,712
mg.metric-geometry;sequences-and-series;limits-and-convergence;intuition
2026-03-04 15:46:01Z
<div class="s-prose js-post-body" itemprop="text"> <p>In the diagram, circles of the same color are congruent.</p> <p><a href="https://i.sstatic.net/4XXO2ILj.png" rel="noreferrer"><img alt="Sequence of nested figure eights" src="https://i.sstatic.net/4XXO2ILj.png"/></a></p> <p>I have a <a href="https://math.stackexchan...
[ { "author_id": 172802, "author_name": "Saúl RM", "author_url": "https://mathoverflow.net/users/172802/sa%c3%bal-rm", "body_html": "<span class=\"comment-copy\" itemprop=\"text\">Why is the proof non-intuitive? If you mean all the big formulas, they can be avoided in a proof, i.e. one does not need a...
[ { "answer_id": 508712, "author_id": 36721, "author_name": "Iosif Pinelis", "author_reputation": 146947, "author_url": "https://mathoverflow.net/users/36721/iosif-pinelis", "body_html": "<div class=\"s-prose js-post-body\" itemprop=\"text\">\n<p>As <a href=\"https://mathoverflow.net/questions...
508,490
Proving Kashiwara–Schapira's micro-local cutoff lemma $\infty$-categorically
https://mathoverflow.net/questions/508490/proving-kashiwara-schapiras-micro-local-cutoff-lemma-infty-categorically
7
271
0
false
false
null
sheaf-theory;micro-local-analysis
2026-03-04 15:14:22Z
[]
[]
508,585
Improperness of regular conditional probabilities
https://mathoverflow.net/questions/508585/improperness-of-regular-conditional-probabilities
1
86
0
false
false
null
pr.probability;measure-theory
2026-03-04 14:47:17Z
[]
[]
391,124
Are hypergeometric series not taught often at universities nowadays, and if so, why?
https://mathoverflow.net/questions/391124/are-hypergeometric-series-not-taught-often-at-universities-nowadays-and-if-so
52
8,000
7
true
false
null
mathematics-education;hypergeometric-functions
2026-03-04 14:28:14Z
[]
[]
508,738
Reference for colimits in comma categories F ↓ G in which F and G are not assumed cocontinuous
https://mathoverflow.net/questions/508738/reference-for-colimits-in-comma-categories-f-%e2%86%93-g-in-which-f-and-g-are-not-assume
3
57
0
false
false
null
reference-request;ct.category-theory;limits-and-colimits
2026-03-04 11:08:40Z
<div class="s-prose js-post-body" itemprop="text"> <p>Given functors <span class="math-container">$F : \mathbf A \to \mathbf C$</span> and <span class="math-container">$G : \mathbf B \to \mathbf C$</span>, it is <a href="https://ncatlab.org/nlab/show/comma+category#completeness_and_cocompleteness" rel="nofollow norefer...
[]
[]
456,780
Reference for understanding Shelah-Harrington-Makkai's proof of Vaught's conjecture for $\omega$-stable theories
https://mathoverflow.net/questions/456780/reference-for-understanding-shelah-harrington-makkais-proof-of-vaughts-conject
6
359
0
false
false
null
reference-request;lo.logic;model-theory
2026-03-04 09:41:17Z
<div class="s-prose js-post-body" itemprop="text"> <p>I'm looking for a source to help me better understand Shelah-Harrington-Makkai's proof of Vaught's conjecture for <span class="math-container">$\omega$</span>-stable theories (<a href="https://doi.org/10.1007/BF02760651" rel="nofollow noreferrer">DOI</a>, <a href="h...
[ { "author_id": 83901, "author_name": "James E Hanson", "author_url": "https://mathoverflow.net/users/83901/james-e-hanson", "body_html": "<span class=\"comment-copy\" itemprop=\"text\">Hopefully someone will come in with a reference but my impression is that there isn't a lot of good exposition of s...
[]
508,666
Cutting squares and rectangles into mutually similar but non-congruent rectangles -2
https://mathoverflow.net/questions/508666/cutting-squares-and-rectangles-into-mutually-similar-but-non-congruent-rectangle
3
163
1
true
true
508,673
co.combinatorics;discrete-geometry;tiling
2026-03-04 08:39:15Z
<div class="s-prose js-post-body" itemprop="text"> <p>We try to go a step beyond <a href="https://mathoverflow.net/questions/508628/cutting-squares-and-rectangles-into-mutually-similar-but-non-congruent-rectangle">Cutting squares and rectangles into mutually similar but non-congruent rectangles</a> and record a couple ...
[ { "author_id": 46140, "author_name": "Peter Taylor", "author_url": "https://mathoverflow.net/users/46140/peter-taylor", "body_html": "<span class=\"comment-copy\" itemprop=\"text\">Trivially, if a rectangle is dissected into two rectangles which are similar to each other and have side ratio $a$ then...
[ { "answer_id": 508673, "author_id": 46140, "author_name": "Peter Taylor", "author_reputation": 8178, "author_url": "https://mathoverflow.net/users/46140/peter-taylor", "body_html": "<div class=\"s-prose js-post-body\" itemprop=\"text\">\n<p>As noted in a comment, but for completeness: if we ...
415,209
Exposition of Grothendieck's mathematics
https://mathoverflow.net/questions/415209/exposition-of-grothendiecks-mathematics
40
7,000
13
true
false
null
ag.algebraic-geometry;soft-question;textbook-recommendation;books;exposition
2026-03-04 08:04:30Z
<div class="s-prose js-post-body" itemprop="text"> <p>As <a href="https://en.wikipedia.org/wiki/Alexander_Grothendieck" rel="noreferrer">Wikipedia</a> says:</p> <blockquote> <p>In Grothendieck's retrospective <em>Récoltes et Semailles</em>, he identified twelve of his contributions which he believed qualified as "great...
[ { "author_id": 148448, "author_name": "Aravindh Krishnamoorthy", "author_url": "https://mathoverflow.net/users/148448/aravindh-krishnamoorthy", "body_html": "<span class=\"comment-copy\" itemprop=\"text\">May I suggest to include the two examples into (separate) answers just to know (as someone else...
[ { "answer_id": 415212, "author_id": null, "author_name": "Francesco Polizzi", "author_reputation": 68975, "author_url": "", "body_html": "<div class=\"s-prose js-post-body\" itemprop=\"text\">\n<p>A good roadmap for FGA (topic 4, with glimpses on topic 6) is</p>\n<p><em>Fantechi, Barbara; Gö...
508,715
Representing a given vector field in any way I like around regular points
https://mathoverflow.net/questions/508715/representing-a-given-vector-field-in-any-way-i-like-around-regular-points
6
163
2
true
false
null
dg.differential-geometry;ap.analysis-of-pdes;differential-topology;differential-equations;smooth-manifolds
2026-03-04 07:52:53Z
<div class="s-prose js-post-body" itemprop="text"> <p>The same question was asked <a href="https://math.stackexchange.com/questions/5126824/representing-vector-field-in-anyway-i-like-around-regular-points">on Mathematics Stack exchange</a> but has not received any response or comments.</p> <p>Let <span class="math-cont...
[ { "author_id": 5484, "author_name": "Daniel Asimov", "author_url": "https://mathoverflow.net/users/5484/daniel-asimov", "body_html": "<span class=\"comment-copy\" itemprop=\"text\">Shouldn't 1. read \"𝑎^1 ≡ 1, 𝑎^i ≡ 0 if i ≠ 1\" ?</span>", "comment_id": 1325539, "created_date": "2026-03-...
[ { "answer_id": 508735, "author_id": 24309, "author_name": "Loïc Teyssier", "author_reputation": 5632, "author_url": "https://mathoverflow.net/users/24309/lo%c3%afc-teyssier", "body_html": "<div class=\"s-prose js-post-body\" itemprop=\"text\">\n<p>For question 2., even for analytic (or polyn...
508,718
A series related to $\zeta(3)$
https://mathoverflow.net/questions/508718/a-series-related-to-zeta3
3
379
2
true
true
508,731
nt.number-theory;sequences-and-series;riemann-zeta-function;binomial-coefficients
2026-03-04 06:33:42Z
<div class="s-prose js-post-body" itemprop="text"> <p>Inspired by <a href="https://mathoverflow.net/questions/508663">Question 508663</a>, I discovered the following identity</p> <p><span class="math-container">$$\sum_{k=1}^\infty\frac{H_{2k}-H_{k}}{k^2\binom{2k}k}=2 \zeta(3)-\frac{\pi \sqrt{3}\, \Psi^{\left(1\right)...
[ { "author_id": 110710, "author_name": "Steven Clark", "author_url": "https://mathoverflow.net/users/110710/steven-clark", "body_html": "<span class=\"comment-copy\" itemprop=\"text\">Mathematica gives the result $$\\sum _{k=1}^{\\infty } \\frac{H_{2 k}-H_k}{k^2 \\binom{2 k}{k}}=2 \\zeta (3)-\\frac{2...
[ { "answer_id": 508731, "author_id": 124654, "author_name": "Zhi-Wei Sun", "author_reputation": 18678, "author_url": "https://mathoverflow.net/users/124654/zhi-wei-sun", "body_html": "<div class=\"s-prose js-post-body\" itemprop=\"text\">\n<p>The formula is not new. It follows from (3.2) and ...
98,548
In search of an early picture of Max Dehn
https://mathoverflow.net/questions/98548/in-search-of-an-early-picture-of-max-dehn
20
1,000
3
true
true
98,550
ho.history-overview
2026-03-04 06:16:24Z
<div class="s-prose js-post-body" itemprop="text"> <p>I am trying to find a copy of a picture "Mathematische Gesellschaft: Group Portrait, Faculty, University of Göttingen (1899)."</p> <p>This picture was published by Springer-Verlag as a poster in 1985, but Springer has been unable to find a copy for me. I also sent ...
[]
[ { "answer_id": 98550, "author_id": 9652, "author_name": "Dirk", "author_reputation": 13198, "author_url": "https://mathoverflow.net/users/9652/dirk", "body_html": "<div class=\"s-prose js-post-body\" itemprop=\"text\">\n<p>As a matter of fact, the poster is right on the other side of the hal...
507,298
Explicit derivation of the Artin-Schreier equation from a Kummer extension in non-discretely valued complete fields
https://mathoverflow.net/questions/507298/explicit-derivation-of-the-artin-schreier-equation-from-a-kummer-extension-in-no
6
270
1
true
false
null
nt.number-theory;field-extensions;valuation-rings
2026-03-04 05:57:07Z
<div class="s-prose js-post-body" itemprop="text"> <p>Let <span class="math-container">$(K, |\cdot|)$</span> be a complete ultrametric field of characteristic <span class="math-container">$0$</span> with residue field <span class="math-container">$k$</span> of characteristic <span class="math-container">$p &gt; 0$</spa...
[ { "author_id": 11417, "author_name": "Lubin", "author_url": "https://mathoverflow.net/users/11417/lubin", "body_html": "<span class=\"comment-copy\" itemprop=\"text\">In future, please have pity on an aged mathematician with failing vision, and avoid using “$a$” and “$\\alpha$” in the same paragrap...
[ { "answer_id": 507322, "author_id": 18060, "author_name": "Will Sawin", "author_reputation": 166969, "author_url": "https://mathoverflow.net/users/18060/will-sawin", "body_html": "<div class=\"s-prose js-post-body\" itemprop=\"text\">\n<p>If <span class=\"math-container\">$a$</span> has the ...
25,630
Major mathematical advances past age fifty
https://mathoverflow.net/questions/25630/major-mathematical-advances-past-age-fifty
73
44,000
43
true
false
null
soft-question;ho.history-overview
2026-03-04 05:39:20Z
<div class="s-prose js-post-body" itemprop="text"> <p>From A Mathematician’s Apology, G. H. Hardy, 1940: "I had better say something here about this question of age, since it is particularly important for mathematicians. No mathematician should ever allow himself to forget that mathematics, more than any other art or s...
[ { "author_id": 6101, "author_name": "Pietro Majer", "author_url": "https://mathoverflow.net/users/6101/pietro-majer", "body_html": "<span class=\"comment-copy\" itemprop=\"text\">Rmk: Hardy suffered of depression, and was living not exactly in the most suitable environment for that. Unfortunately, t...
[ { "answer_id": 25631, "author_id": null, "author_name": "David Hansen", "author_reputation": 13308, "author_url": "", "body_html": "<div class=\"s-prose js-post-body\" itemprop=\"text\">\n<p>Roger Apery was 62 when he proved the irrationality of $\\zeta(3)$.</p>\n</div>", "comments": [ ...
379,866
Conceptual proof of braid group actions on quantum groups
https://mathoverflow.net/questions/379866/conceptual-proof-of-braid-group-actions-on-quantum-groups
7
637
1
true
false
null
rt.representation-theory;qa.quantum-algebra;quantum-groups;geometric-representation-theory
2026-03-04 20:25:05Z
<div class="s-prose js-post-body" itemprop="text"> <p>Roughly 1990, Lusztig wrote a series of papers on quantum groups. Perhaps the result that the braid groups acts on <span class="math-container">$U_q(\mathfrak{g})$</span> is the proof which is least conceptual.</p> <p>The original paper contains a case by case check...
[ { "author_id": 91709, "author_name": "Paul Gustafson", "author_url": "https://mathoverflow.net/users/91709/paul-gustafson", "body_html": "<span class=\"comment-copy\" itemprop=\"text\">Have you seen <a href=\"https://mathoverflow.net/a/115252\">mathoverflow.net/a/115252</a> ? In particular, Drinfeld...
[ { "answer_id": 508754, "author_id": 143390, "author_name": "Dat Minh Ha", "author_reputation": 1728, "author_url": "https://mathoverflow.net/users/143390/dat-minh-ha", "body_html": "<div class=\"s-prose js-post-body\" itemprop=\"text\">\n<p>For the braid group actions on Yangians and on quan...
508,755
Hanner's unpublished example of a non-fiber bundle
https://mathoverflow.net/questions/508755/hanners-unpublished-example-of-a-non-fiber-bundle
10
120
0
false
false
null
gn.general-topology;fibre-bundles;principal-bundles
2026-03-04 20:26:04Z
<div class="s-prose js-post-body" itemprop="text"> <p>Given a topological group <span class="math-container">$G$</span> and a closed subgroup <span class="math-container">$H \le G$</span>, one can ask when the projection map <span class="math-container">$G \to G/H$</span> is a fiber bundle. In Steenrod's book on fiber ...
[]
[]
487,398
Niveau of the Hodge structure of an hypersurface in $\mathbb{P}^n$
https://mathoverflow.net/questions/487398/niveau-of-the-hodge-structure-of-an-hypersurface-in-mathbbpn
1
351
1
true
false
null
ag.algebraic-geometry;hodge-theory;intersection-theory;hypersurfaces
2026-03-04 21:07:35Z
<div class="s-prose js-post-body" itemprop="text"> <p>Assume <span class="math-container">$X:=X_d$</span> is an hypersurface of degree <span class="math-container">$d$</span> in <span class="math-container">$\mathbb{P}^n$</span>. Assume in addition that <span class="math-container">$d&lt;n+1$</span>, hence <span class=...
[ { "author_id": 13265, "author_name": "Jason Starr", "author_url": "https://mathoverflow.net/users/13265/jason-starr", "body_html": "<span class=\"comment-copy\" itemprop=\"text\">Are you asking how to extend the Griffiths residue calculus to complete intersections in generalized flag varieties (not ...
[ { "answer_id": 487402, "author_id": 4428, "author_name": "Sasha", "author_reputation": 42266, "author_url": "https://mathoverflow.net/users/4428/sasha", "body_html": "<div class=\"s-prose js-post-body\" itemprop=\"text\">\n<p>Since <span class=\"math-container\">$H^{p,q}(X) = H^q(X,\\Omega^p...
371,129
Where can I read about Veblen functions / klammersymbols beyond the large Veblen ordinal?
https://mathoverflow.net/questions/371129/where-can-i-read-about-veblen-functions-klammersymbols-beyond-the-large-veblen
3
398
2
true
false
null
set-theory;lo.logic;ordinal-numbers
2026-03-05 06:41:04Z
<div class="s-prose js-post-body" itemprop="text"> <p>So, I'm not sure to what extent this is a thing. John Baez mentions in <a href="https://johncarlosbaez.wordpress.com/2016/07/07/large-countable-ordinals-part-3/" rel="nofollow noreferrer">this blog post</a> that common large countable ordinals beyond the large Vebl...
[ { "author_id": 36385, "author_name": "Fedor Pakhomov", "author_url": "https://mathoverflow.net/users/36385/fedor-pakhomov", "body_html": "<span class=\"comment-copy\" itemprop=\"text\">If one takes Veblen-like construction as an informal concept, then it would be hard to justify some $\\alpha&lt;\\o...
[ { "answer_id": 371199, "author_id": 62695, "author_name": "Andreas Weiermann", "author_reputation": 471, "author_url": "https://mathoverflow.net/users/62695/andreas-weiermann", "body_html": "<div class=\"s-prose js-post-body\" itemprop=\"text\">\n<p>Here is some relevant information by a gra...
508,777
Please help me with this AWESOME Goldbach Conjecture idea! [closed]
https://mathoverflow.net/questions/508777/please-help-me-with-this-awesome-goldbach-conjecture-idea
0
37
0
false
false
null
prime-numbers;open-problems;factorization;goldbach-type-problems
2026-03-05 10:02:07Z
<div class="s-prose js-post-body" itemprop="text"> <div> <aside class="s-notice s-notice__info post-notice js-post-notice mb16" role="status"> <div class="d-flex fd-column fw-nowrap"> <div class="d-flex fw-nowrap"> <div class="flex--item wmn0 fl1 lh-lg"> <div class="flex--item fl1 lh-lg"> <div> ...
[]
[]
502,120
Examples for the use of AI and especially LLMs in notable mathematical developments
https://mathoverflow.net/questions/502120/examples-for-the-use-of-ai-and-especially-llms-in-notable-mathematical-developme
56
11,000
20
true
false
null
big-list;computer-science;examples;big-picture;experimental-mathematics
2026-03-05 09:46:23Z
<div class="s-prose js-post-body" itemprop="text"> <blockquote> <h3>The purpose of this question is to collect examples where large language models (LLMs) like ChatGPT have led to notable mathematical developments.</h3> </blockquote> <p>The emphasis in this question is on LLMs, but answers about other machine-learning ...
[ { "author_id": 25028, "author_name": "Sam Hopkins", "author_url": "https://mathoverflow.net/users/25028/sam-hopkins", "body_html": "<span class=\"comment-copy\" itemprop=\"text\">There have been many similar questions on MO to this about the use of AI/machine learning in research math; see, e.g., <a...
[ { "answer_id": 503160, "author_id": null, "author_name": "Lior Silberman", "author_reputation": 2873, "author_url": "", "body_html": "<div class=\"s-prose js-post-body\" itemprop=\"text\">\n<p>Boris Alexeev and Dustin Mixon posted last week their paper <a href=\"https://arxiv.org/abs/2510.19...
508,737
Ordinals embeddable into the collection of strictly increasing functions $f:\omega\to\omega$
https://mathoverflow.net/questions/508737/ordinals-embeddable-into-the-collection-of-strictly-increasing-functions-f-ome
6
236
2
true
true
508,740
set-theory;lo.logic;order-theory;lattice-theory;ordinal-numbers
2026-03-05 09:24:58Z
<div class="s-prose js-post-body" itemprop="text"> <p>Let <span class="math-container">$\text{I}(\omega)$</span> denote the collection of strictly increasing functions <span class="math-container">$f:\omega\to\omega$</span> and consider the poset <span class="math-container">$\big(\text{I}(\omega),\leq_\omega\big)$</sp...
[]
[ { "answer_id": 508740, "author_id": 30186, "author_name": "Wojowu", "author_reputation": 34953, "author_url": "https://mathoverflow.net/users/30186/wojowu", "body_html": "<div class=\"s-prose js-post-body\" itemprop=\"text\">\n<p>The answer is <span class=\"math-container\">$\\omega_1$</span...
508,774
More conjectural formulas for Riemann's zeta function (II)
https://mathoverflow.net/questions/508774/more-conjectural-formulas-for-riemanns-zeta-function-ii
0
43
0
false
false
null
nt.number-theory;sequences-and-series;riemann-zeta-function;binomial-coefficients;combinatorial-identities
2026-03-05 09:22:33Z
<div class="s-prose js-post-body" itemprop="text"> <p>Motivated by Zeilberger's series <span class="math-container">$$\sum_{k=1}^\infty\frac{21k-8}{k^3\binom{2k}k^3}=\zeta(2)$$</span> and Questions <a href="https://mathoverflow.net/questions/508743">508743</a> and <a href="https://mathoverflow.net/questions/508768">508...
[]
[]
508,768
More conjectural formulas for Riemann's zeta function
https://mathoverflow.net/questions/508768/more-conjectural-formulas-for-riemanns-zeta-function
2
115
0
false
false
null
nt.number-theory;sequences-and-series;riemann-zeta-function;binomial-coefficients;combinatorial-identities
2026-03-05 09:21:58Z
<div class="s-prose js-post-body" itemprop="text"> <p>Motivated by <a href="https://mathoverflow.net/questions/508743">Question 508743</a> and the known identities</p> <p><span class="math-container">$$\sum_{k=1}^\infty\frac{(-1)^k}{k^3\binom{2k}k}=-\frac25\zeta(3)\ \ \text{and}\ \ \sum_{k=1}^\infty\frac1{k^4\binom{2k}...
[ { "author_id": 124654, "author_name": "Zhi-Wei Sun", "author_url": "https://mathoverflow.net/users/124654/zhi-wei-sun", "body_html": "<span class=\"comment-copy\" itemprop=\"text\">(II1) is equivalent to (3.15) of my 2015 paper available from <a href=\"http://maths.nju.edu.cn/~zwsun/165s.pdf\" rel=\...
[]
508,775
Characterization of spacelike simplices in $1+n$-dimensional Minkowski
https://mathoverflow.net/questions/508775/characterization-of-spacelike-simplices-in-1n-dimensional-minkowski
2
13
0
false
false
null
mg.metric-geometry;convex-geometry;simplicial-stuff;special-relativity;minkowski-space
2026-03-05 09:21:22Z
<div class="s-prose js-post-body" itemprop="text"> <p>Let <span class="math-container">$\mathbb M^n = \mathbb R^{1,n-1}$</span> be <span class="math-container">$n$</span>-dimensional Minkowski space and <span class="math-container">$\eta\colon \mathbb M^n \times \mathbb M^n \to \mathbb R $</span> the corresponding inde...
[ { "author_id": 13842, "author_name": "Dmitrii Korshunov", "author_url": "https://mathoverflow.net/users/13842/dmitrii-korshunov", "body_html": "<span class=\"comment-copy\" itemprop=\"text\">Pick any vertex $x_1$ of your simplex, then it is a problem to decide if the linear space spanned by $x_i-x_1...
[]
508,621
Primes of the form $x^2+ny^2$ when the class group is $C_2C_4$
https://mathoverflow.net/questions/508621/primes-of-the-form-x2ny2-when-the-class-group-is-c-2c-4
3
201
0
false
false
null
nt.number-theory;algebraic-number-theory;class-field-theory
2026-03-05 07:44:40Z
<div class="s-prose js-post-body" itemprop="text"> <p>In my <a href="https://mathoverflow.net/questions/507906/primes-of-the-form-p-x2ny2-when-the-class-number-is-8">previous</a> question, I asked about the quadratic forms of class number 8. While it answered my question about how to get the correct splitting polynomia...
[ { "author_id": 3324, "author_name": "Will Jagy", "author_url": "https://mathoverflow.net/users/3324/will-jagy", "body_html": "<span class=\"comment-copy\" itemprop=\"text\">I'm fiddling with $x^2 + 65 y^2.$ What do you say happens? Oh, not cyclic, all have exponent 4.</span>", "comment_id": 132...
[]
508,743
Some series related to $\zeta(3),\zeta(4),\zeta(5),\zeta(6),\zeta(7)$
https://mathoverflow.net/questions/508743/some-series-related-to-zeta3-zeta4-zeta5-zeta6-zeta7
11
356
1
true
false
null
nt.number-theory;sequences-and-series;riemann-zeta-function;combinatorial-identities
2026-03-05 07:19:54Z
<div class="s-prose js-post-body" itemprop="text"> <p>Let <span class="math-container">$$f(k)=\frac{1}{k^2\binom{2 k}{k}},$$</span> and <span class="math-container">$$f^{(n)}(k)=\frac{d^n}{dk^n} f(k).$$</span> Inspired by <a href="https://mathoverflow.net/questions/508718">Question 508718</a>, I discovered the followin...
[ { "author_id": 81776, "author_name": "Henri Cohen", "author_url": "https://mathoverflow.net/users/81776/henri-cohen", "body_html": "<span class=\"comment-copy\" itemprop=\"text\">$$\\sum_{k=1}^\\infty f^{(6)}(k)=(110483/12)\\zeta(8)-5088\\zeta(3)\\zeta(5)+960\\zeta(2)\\zeta(3)^2-672\\zeta(3,5)$$ whe...
[ { "answer_id": 508761, "author_id": 58345, "author_name": "eddy ardonne", "author_reputation": 673, "author_url": "https://mathoverflow.net/users/58345/eddy-ardonne", "body_html": "<div class=\"s-prose js-post-body\" itemprop=\"text\">\n<p>This is a partial answer to question 3., that does n...
508,468
Availability of Medusa algorithm implementations
https://mathoverflow.net/questions/508468/availability-of-medusa-algorithm-implementations
3
228
1
true
false
null
complex-dynamics;mathematical-software
2026-03-05 06:56:33Z
<div class="s-prose js-post-body" itemprop="text"> <div> <aside class="s-notice s-notice__info post-notice js-post-notice mb16 js-bounty-notification" role="status"> <div class="d-flex fd-column fw-nowrap"> <div class="d-flex fw-nowrap"> <div class="flex--item mr8"> <svg aria-hidden="true" class="svg-icon iconClock" he...
[ { "author_id": 134299, "author_name": "Michael Engelhardt", "author_url": "https://mathoverflow.net/users/134299/michael-engelhardt", "body_html": "<span class=\"comment-copy\" itemprop=\"text\">macOS is a Unix system.</span>", "comment_id": 1324993, "created_date": "2026-02-26 14:59:54Z", ...
[ { "answer_id": 508773, "author_id": 101028, "author_name": "LegionMammal978", "author_reputation": 741, "author_url": "https://mathoverflow.net/users/101028/legionmammal978", "body_html": "<div class=\"s-prose js-post-body\" itemprop=\"text\">\n<p>I have uploaded a set of patches at <a href=...
508,771
Quandle and homeomorphism of spaces
https://mathoverflow.net/questions/508771/quandle-and-homeomorphism-of-spaces
0
20
0
false
false
null
quandles
2026-03-05 06:23:58Z
<div class="s-prose js-post-body" itemprop="text"> <p>Does a homeomorphism between pairs of spaces induce an isomorphism of the fundamental quandle?</p> </div>
[ { "author_id": 9417, "author_name": "Jim Conant", "author_url": "https://mathoverflow.net/users/9417/jim-conant", "body_html": "<span class=\"comment-copy\" itemprop=\"text\">AFAIK, the fundamental quandle is not defined for an arbitrary space, just for knot complements.</span>", "comment_id": 1...
[]
508,707
Existence of limit intersection in an $\omega_1$-chain of almost decreasing subsets of $\omega$
https://mathoverflow.net/questions/508707/existence-of-limit-intersection-in-an-omega-1-chain-of-almost-decreasing-subs
10
216
1
true
true
508,741
set-theory;infinite-combinatorics
2026-03-04 21:18:35Z
<div class="s-prose js-post-body" itemprop="text"> <p>Is it consistent that there exists a <span class="math-container">$\subseteq^*$</span>-decreasing chain <span class="math-container">$(X_\alpha)_{\alpha&lt;\omega_1}$</span> of infinite subsets of <span class="math-container">$\omega$</span> such that for all ordina...
[ { "author_id": 30186, "author_name": "Wojowu", "author_url": "https://mathoverflow.net/users/30186/wojowu", "body_html": "<span class=\"comment-copy\" itemprop=\"text\">What is $\\subseteq^*$?</span>", "comment_id": 1325511, "created_date": "2026-03-03 14:06:43Z", "score": 1 }, { ...
[ { "answer_id": 508741, "author_id": 103802, "author_name": "Jonathan Schilhan", "author_reputation": 483, "author_url": "https://mathoverflow.net/users/103802/jonathan-schilhan", "body_html": "<div class=\"s-prose js-post-body\" itemprop=\"text\">\n<p>No.</p>\n<p>If given <span class=\"math-...
507,483
Proving bounds for function set with similarities to Legendre polynomials
https://mathoverflow.net/questions/507483/proving-bounds-for-function-set-with-similarities-to-legendre-polynomials
2
210
0
false
false
null
real-analysis;ca.classical-analysis-and-odes;lower-bounds;legendre-polynomials;upper-bounds
2026-03-05 05:53:08Z
<div class="s-prose js-post-body" itemprop="text"> <div> <aside class="s-notice s-notice__info post-notice js-post-notice mb16 js-bounty-notification" role="status"> <div class="d-flex fd-column fw-nowrap"> <div class="d-flex fw-nowrap"> <div class="flex--item mr8"> <svg aria-hidden="true" class="svg-icon iconClock" he...
[ { "author_id": 129185, "author_name": "mathworker21", "author_url": "https://mathoverflow.net/users/129185/mathworker21", "body_html": "<span class=\"comment-copy\" itemprop=\"text\">you doubt which proof is feasible?</span>", "comment_id": 1321797, "created_date": "2026-01-27 09:19:53Z", ...
[]
508,770
Classification of symmetric bilinear forms over Laurent polynomial ring under congruence and Schur complement
https://mathoverflow.net/questions/508770/classification-of-symmetric-bilinear-forms-over-laurent-polynomial-ring-under-co
1
21
0
false
false
null
ac.commutative-algebra;polynomials;finite-fields;quadratic-forms;schur-complement
2026-03-05 04:46:20Z
<div class="s-prose js-post-body" itemprop="text"> <p>Consider the ring <span class="math-container">$R$</span> of Laurent polynomials in <span class="math-container">$n$</span> variables over the finite field of two elements, <span class="math-container">$R= \mathbb F_2[x_0,x_0^{-1},x_1,x_1^{-1},\ldots]$</span>, with ...
[]
[]
508,769
Conjectural series for $L(s,\genfrac(){}{}{-3}\cdot)$
https://mathoverflow.net/questions/508769/conjectural-series-for-ls-genfrac-3-cdot
0
49
0
false
false
null
nt.number-theory;sequences-and-series;binomial-coefficients;l-functions;combinatorial-identities
2026-03-05 03:39:47Z
<div class="s-prose js-post-body" itemprop="text"> <p><span class="math-container">$\newcommand\Ksymb{\genfrac(){}{}}$</span>For <span class="math-container">$s=1,2,3,\dotsc$</span>, let us define <span class="math-container">$$L_{-3}(s):=L\left(s,\Ksymb{-3}\cdot\right)=\sum_{k=1}^\infty\frac{\Ksymb{-3}k}{k^s}=\sum_{n=...
[]
[]
508,739
Numbers between twin primes
https://mathoverflow.net/questions/508739/numbers-between-twin-primes
6
475
1
true
false
null
nt.number-theory;prime-numbers
2026-03-05 02:25:33Z
<div class="s-prose js-post-body" itemprop="text"> <p>I am turning 72 this year, an abundant number between a pair of twin primes. We do not know yet whether or not there are infinitely many twin primes, but can I be certain that at least most numbers, more than half inside the pairs of twin primes (.e. <span class="ma...
[ { "author_id": 30186, "author_name": "Wojowu", "author_url": "https://mathoverflow.net/users/30186/wojowu", "body_html": "<span class=\"comment-copy\" itemprop=\"text\">Primes themselves are not abundant, so it seems the question is about the density of abundant numbers. As stated on <a href=\"https...
[ { "answer_id": 508748, "author_id": 586494, "author_name": "Elias Panholzer", "author_reputation": 140, "author_url": "https://mathoverflow.net/users/586494/elias-panholzer", "body_html": "<div class=\"s-prose js-post-body\" itemprop=\"text\">\n<p>Every multiple of <span class=\"math-contain...
416,763
Intersection of the kernel with the interpolation space
https://mathoverflow.net/questions/416763/intersection-of-the-kernel-with-the-interpolation-space
1
414
1
true
false
null
fa.functional-analysis;sobolev-spaces;interpolation-spaces
2026-03-05 02:03:35Z
<div class="s-prose js-post-body" itemprop="text"> <p><span class="math-container">$\DeclareMathOperator\Ker{Ker}$</span>Given two Banach spaces <span class="math-container">$X$</span> and <span class="math-container">$Y$</span> with a continuous inclusion <span class="math-container">$X\subset Y$</span>, and another c...
[ { "author_id": 3948, "author_name": "Willie Wong", "author_url": "https://mathoverflow.net/users/3948/willie-wong", "body_html": "<span class=\"comment-copy\" itemprop=\"text\">Is your counterexample really a counterexample? What norms are you putting on $X\\cap Z$ and on $Z$? In some sense the \"co...
[ { "answer_id": 416820, "author_id": null, "author_name": "Willie Wong", "author_reputation": 42242, "author_url": "https://mathoverflow.net/users/3948", "body_html": "<div class=\"s-prose js-post-body\" itemprop=\"text\">\n<p>(Making CW as this is an extended comment.)</p>\n<p>Let's generali...
508,763
Intersection of centralizers in $S_n$
https://mathoverflow.net/questions/508763/intersection-of-centralizers-in-s-n
1
92
1
true
false
null
gr.group-theory;finite-groups;symmetric-groups;centralisers
2026-03-05 01:53:05Z
<div class="s-prose js-post-body" itemprop="text"> <p>Let <span class="math-container">$Z(g_1)$</span> and <span class="math-container">$Z(g_2)$</span> be the centralizers of two permutations <span class="math-container">$g_1$</span> and <span class="math-container">$g_2$</span> in the symmetric group <span class="math...
[ { "author_id": 2383, "author_name": "LSpice", "author_url": "https://mathoverflow.net/users/2383/lspice", "body_html": "<span class=\"comment-copy\" itemprop=\"text\">What does it mean to calculate it as a subgroup of $S_n$? To enumerate the elements?</span>", "comment_id": 1325664, "create...
[ { "answer_id": 508764, "author_id": 35840, "author_name": "Derek Holt", "author_reputation": 38726, "author_url": "https://mathoverflow.net/users/35840/derek-holt", "body_html": "<div class=\"s-prose js-post-body\" itemprop=\"text\">\n<p>The intersection of the centralizers of <span class=\"...
508,746
Multiplicativity conjecture for odd-index derangements
https://mathoverflow.net/questions/508746/multiplicativity-conjecture-for-odd-index-derangements
0
81
0
false
false
null
co.combinatorics
2026-03-04 23:43:11Z
<div class="s-prose js-post-body" itemprop="text"> <blockquote> <p><strong>Conjecture.</strong> Let <span class="math-container">$D_n$</span> denote the number of derangements on <span class="math-container">$n$</span> and <span class="math-container">$S$</span> denote the set of all <span class="math-container">$k$</s...
[]
[]
508,758
Topology on the set of smooth sections of a smooth fiber bundle
https://mathoverflow.net/questions/508758/topology-on-the-set-of-smooth-sections-of-a-smooth-fiber-bundle
1
88
1
true
false
null
dg.differential-geometry;differential-topology;frechet-manifold
2026-03-04 22:34:56Z
<div class="s-prose js-post-body" itemprop="text"> <p>Let <span class="math-container">$p: B \to M$</span> be a smooth fiber bundle. Denote <span class="math-container">$\Gamma(B)$</span> the set of smooth sections. What is the natural topology on this set?</p> <p>It is often viewed as a Frechet manifold. For example, ...
[ { "author_id": 4177, "author_name": "David Roberts", "author_url": "https://mathoverflow.net/users/4177/david-roberts", "body_html": "<span class=\"comment-copy\" itemprop=\"text\">If M is compact then yes, it's a Fréchet manifold.</span>", "comment_id": 1325652, "created_date": "2026-03-04 ...
[ { "answer_id": 508762, "author_id": 129074, "author_name": "Pierre PC", "author_reputation": 4203, "author_url": "https://mathoverflow.net/users/129074/pierre-pc", "body_html": "<div class=\"s-prose js-post-body\" itemprop=\"text\">\n<p>People usually consider one of the two <a href=\"https:...
508,750
Minimum degree in a graph defined by sumsets
https://mathoverflow.net/questions/508750/minimum-degree-in-a-graph-defined-by-sumsets
2
124
1
true
true
508,760
co.combinatorics;graph-theory;additive-combinatorics;sumsets
2026-03-04 22:13:57Z
<div class="s-prose js-post-body" itemprop="text"> <p>I have the following conjecture.</p> <p><strong>Conjecture.</strong> <em>Let <span class="math-container">$A$</span> be a finite set in some abelian group <span class="math-container">$G$</span>, and let <span class="math-container">$A = B\cup B'$</span> be a partit...
[]
[ { "answer_id": 508760, "author_id": 7709, "author_name": "Mark Wildon", "author_reputation": 12112, "author_url": "https://mathoverflow.net/users/7709/mark-wildon", "body_html": "<div class=\"s-prose js-post-body\" itemprop=\"text\">\n<p>Here is a family of counterexamples using elementary a...
508,710
What is the Joyal model structure actually useful for?
https://mathoverflow.net/questions/508710/what-is-the-joyal-model-structure-actually-useful-for
16
593
1
true
false
null
ct.category-theory;higher-category-theory;simplicial-stuff;model-categories;infinity-categories
2026-03-04 05:32:13Z
<div class="s-prose js-post-body" itemprop="text"> <p>I've seen it written that the existence of the Joyal model structure on simplicial sets is one of the foundational results on which the theory of <span class="math-container">$\infty$</span>-categories (or, rather, the theory of quasi-categories as a model of <span ...
[ { "author_id": 2362, "author_name": "Tim Campion", "author_url": "https://mathoverflow.net/users/2362/tim-campion", "body_html": "<span class=\"comment-copy\" itemprop=\"text\">I’m not sure what you mean. What’s an example of a model structure which you do find useful?</span>", "comment_id": 132...
[ { "answer_id": 508716, "author_id": 2362, "author_name": "Tim Campion", "author_reputation": 67580, "author_url": "https://mathoverflow.net/users/2362/tim-campion", "body_html": "<div class=\"s-prose js-post-body\" itemprop=\"text\">\n<p>If you’re reading HTT say, you might not find the exis...