Join us in building a kind, collaborative learning community via our updated Code of Conduct.

MathOverflow is a question and answer site for professional mathematicians. Join them; it only takes a minute:

Sign up

Here's how it works:

Anybody can ask a question
Anybody can answer
The best answers are voted up and rise to the top

Top Questions

active 10 featured hot week month

68

votes

5

answers

10k

views

Has incorrect notation ever led to a mistaken proof?

ct.category-theory soft-question ho.history-overview notation

modified Aug 11 at 17:23 Joel David Hamkins 162k

33

votes

7

answers

3k

views

Paradoxical Mathematical Objects Pending for Construction [on hold]

reference-request gr.group-theory set-theory lo.logic definitions

modified yesterday Stella Biderman 316

29

votes

4

answers

3k

views

Is there an 11-term arithmetic progression of primes beginning with 11?

nt.number-theory prime-numbers arithmetic-progression

answered yesterday Wlod AA 1,156

17

votes

6

answers

892

views

Lebesgue measure theory applications

reference-request measure-theory big-list lebesgue-measure

answered Aug 10 at 16:02 Venkataramana 7,839

14

votes

7

answers

1k

views

Mathematical Writing: Proof Outlines/Overview in a Paper

mathematical-writing slick-proof

modified 10 hours ago Ooker 101

11

votes

1

answer

698

views

A curious valuation of this sequence

nt.number-theory co.combinatorics

modified Aug 10 at 2:46 darij grinberg 16.4k

6

votes

2

answers

417

views

Are there known examples of sets whose power set is equal in size to power set of larger sets only in absence of choice?

set-theory axiom-of-choice

modified 2 days ago Asaf Karagila 20.2k

9

votes

3

answers

323

views

Induced maps on homotopy groups by self maps of $\mathbb{CP}^n$

at.algebraic-topology homotopy-theory

modified Aug 11 at 20:53 Dmitri 17.9k

9

votes

2

answers

410

views

Can we have an infinite sequence of decreasing cardinality all terms of which have equal sized power sets?

set-theory axiom-of-choice

modified yesterday Asaf Karagila 20.2k

6

votes

3

answers

202

views

$S$-dual of filtered spectra

reference-request at.algebraic-topology

modified Aug 9 at 10:28 j.c. 10.6k

8

votes

2

answers

252

views

Hölder continuity for operators

fa.functional-analysis real-analysis ap.analysis-of-pdes ca.classical-analysis-and-odes operator-theory

answered Aug 11 at 13:34 Suvrit 23.2k

8

votes

1

answer

771

views

Are there infinitely many primes of this form?

nt.number-theory analytic-number-theory prime-numbers

modified yesterday isaacg 115

24

votes

1

answer

299

views

Has the $E_8$-based generating function for squares numbers been proven?

nt.number-theory co.combinatorics mp.mathematical-physics conformal-field-theory combinatorial-identities

answered 8 hours ago Gjergji Zaimi 57.4k

8

votes

5

answers

311

views

Reference request: Recovering a Riemannian metric from the distance function

reference-request dg.differential-geometry riemannian-geometry

modified Aug 10 at 7:42 user_1789 326

13

votes

3

answers

407

views

Union of random intervals with total length equal to infinity

pr.probability

modified 10 hours ago GH from MO 55.2k

8

votes

2

answers

581

views

The Stacks project

ag.algebraic-geometry reference-request textbook-recommendation online-resources

answered Aug 10 at 17:13 pbelmans 969

5

votes

3

answers

283

views

Formalizations of the idea that something is a function of something else?

lo.logic formal-languages type-theory categorical-logic formalization

answered yesterday Lurker 31

8

votes

1

answer

447

views

Whence “Durchschnitt” and “Vereinigung”?

set-theory ho.history-overview terminology notation

modified Aug 10 at 8:50 Carlo Beenakker 68.1k

10

votes

2

answers

365

views

What kind of computer tools topologists/geometrists use to visualize the objects they deal with?

soft-question mathematics-education mathematical-software software

answered Aug 9 at 11:22 Ben Linowitz 5,685

4

votes

4

answers

259

views

Weyl Invariants of a Torus and the Center of a Reductive Group

algebraic-groups root-systems

modified Aug 12 at 1:22 Alexander 327

13

votes

2

answers

329

views

Structures of the space of neural networks

fa.functional-analysis ra.rings-and-algebras convex-geometry

modified 2 days ago Martin Sleziak 2,490

8

votes

1

answer

301

views

What is the interpretation of the Gerstenhaber bracket?

homological-algebra cohomology operads

answered 2 days ago Pavel Safronov 2,407

5

votes

2

answers

324

views

A paradox on the deformation of singularities

ag.algebraic-geometry birational-geometry singularity-theory

modified 15 hours ago j.c. 10.6k

9

votes

1

answer

204

views

Fourth obstruction, Pontryagin and Euler class

dg.differential-geometry at.algebraic-topology vector-bundles characteristic-classes

answered Aug 9 at 15:46 Matthias Wendt 12.9k

2

votes

3

answers

159

views

Complex differential equations

reference-request cv.complex-variables differential-equations

modified Aug 10 at 6:40 user64494 1,392

10

votes

2

answers

166

views

Cycle generating function of permutations with only odd cycles

co.combinatorics permutations symmetric-groups

modified 7 hours ago Richard Stanley 27.7k

11

votes

1

answer

250

views

Determine $2^{\frac{p-1}{4}}\equiv 1\pmod p$ or $2^{\frac{p-1}{4}}\equiv -1\pmod p$ when $p\equiv 1 \pmod 8$

nt.number-theory prime-numbers algebraic-number-theory number-fields

answered Aug 9 at 13:43 François Brunault 10.8k

2

votes

2

answers

166

views

Classification of line bundles by second cohomology of a manifold

smooth-manifolds line-bundles derham-cohomology

answered 12 hours ago abx 21.9k

8

votes

1

answer

171

views

Condition on a differential form arising from the theory of elasticity

dg.differential-geometry differential-forms

modified 14 hours ago Robert Bryant 70.2k

1

vote

3

answers

200

views

References request: representations of classical groups

rt.representation-theory algebraic-groups

modified Aug 9 at 3:07 Jianrong Li 2,265

7

votes

1

answer

288

views

What are some open problems in moduli spaces and moduli stacks?

ag.algebraic-geometry big-list moduli-spaces open-problems

answered Aug 9 at 21:15 SSt 248

3

votes

3

answers

170

views

Extending a continuous map over projective space

ag.algebraic-geometry reference-request linear-algebra gt.geometric-topology

modified yesterday Omnomnomnom 118

1

vote

1

answer

201

views

Sum of log over friables

nt.number-theory analytic-number-theory

answered Aug 9 at 13:17 Khadija Mbarki 672

5

votes

1

answer

119

views

Why is the number of Perfect Matchings in a triangular grid equivalent to the number of Royal Paths?

co.combinatorics graph-theory lattices perfect-matchings

modified Aug 9 at 20:48 NicoDean 122

5

votes

1

answer

276

views

The soccer splitting problem in arbitrary commutative ring

ac.commutative-algebra ra.rings-and-algebras additive-combinatorics

modified 2 days ago François Brunault 10.8k

6

votes

2

answers

202

views

Coverage of balls on random points in Euclidean space

pr.probability packing-and-covering

modified 3 hours ago Joseph O'Rourke 82.7k

22

votes

0

answers

313

views

On a quantum Riemann Hypothesis

nt.number-theory qa.quantum-algebra subfactors riemann-hypothesis planar-algebras

modified 6 hours ago Sebastien Palcoux 7,441

3

votes

1

answer

234

views

Thom space, homotopy group and cohomology group

at.algebraic-topology differential-topology vector-bundles spectral-sequences cobordism

modified 18 hours ago user43326 1,759

2

votes

1

answer

168

views

Name and Algorithms for a Sparsest Circle Packing

mg.metric-geometry algorithms discrete-geometry

modified 2 days ago Manfred Weis 4,084

12

votes

1

answer

238

views

Is $K[[x_1,x_2,\dots]]$ an $\mathfrak m$-adically complete ring?

ac.commutative-algebra power-series

modified 9 hours ago Uriya First 306

3

votes

2

answers

87

views

area variation of a closed surface under ${\rm SL}(3)$

dg.differential-geometry isoperimetry

answered Aug 10 at 6:25 Hee Kwon Lee 516

4

votes

1

answer

110

views

Is the preimage of a face under an affine map a face?

convex-polytopes convex-geometry convex-analysis

modified Aug 10 at 19:24 Robert Furber 949

3

votes

1

answer

76

views

Lower frattini subgroup

finite-groups

answered Aug 10 at 0:25 verret 2,004

4

votes

1

answer

149

views

Is this a random walk? Does it have a name?

pr.probability random-walks

modified 2 days ago Brendan McKay 24.1k

3

votes

2

answers

90

views

Generating Irreducible representations of a simple lie algebra with Schur functors

rt.representation-theory lie-groups algebraic-groups lie-algebras

answered 13 hours ago Ehud Meir 2,916

4

votes

2

answers

112

views

Can we stay invertible while approximating linear maps in Sobolev spaces?

linear-algebra real-analysis sobolev-spaces approximation-theory

modified Aug 9 at 6:16 Pietro Majer 37.8k

2

votes

1

answer

111

views

Is any real closed extension of $\mathbb R$ characterized up to isomorphism by its ladder?

lo.logic model-theory fields

modified Aug 11 at 17:12 LSpice 2,559

2

votes

1

answer

140

views

Maximality with respect to the splitting property

co.combinatorics set-theory infinite-combinatorics

modified yesterday bof 4,250

Looking for more? Browse the complete list of questions, or popular tags. Help us answer unanswered questions.

MathOverflow works best with JavaScript enabled