Famous Question

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Awarded 1449 times.

What role does the "dual Coxeter number" play in Lie theory (and should it be called the "Kac number")?

Awarded 17 hours ago

Jim Humphreys

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Looking for an introduction to orbifolds

Awarded Nov 28 at 4:01

Themaninthebox

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Can a quotient ring R/J ever be flat over R?

Awarded Nov 25 at 12:53

Anton Geraschenko

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For which $c$ is $\mathbb{Z}[\sqrt{c}]$ a unique factorization domain? a Euclidean domain?

Awarded Nov 25 at 7:00

TCL

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Intuition about the cotangent complex?

Awarded Nov 19 at 22:06

Peter Arndt

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On what basis does a paper get accepted into a top journal?

Awarded Nov 18 at 7:34

Nate River

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Can an integral equation always be rewritten as a differential equation?

Awarded Nov 13 at 19:19

Michael Bächtold

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Analogue to covering space for higher homotopy groups?

Awarded Nov 13 at 5:03

j.c.

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Local complete intersections which are not complete intersections

Awarded Nov 10 at 14:43

Adam K

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Upper bounds for the sum of primes up to $n$

Awarded Nov 9 at 9:10

Jernej

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A Bijection Between the Reals and Infinite Binary Strings

Awarded Nov 8 at 4:06

Austin Mohr

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What was Hilbert's view of Gödel's Incompleteness Theorems?

Awarded Nov 7 at 2:00

Thomas Benjamin

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What is the difference between hard and soft analysis?

Awarded Nov 4 at 18:28

Robert Haraway

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Models of ZFC Set Theory - Getting Started

Awarded Nov 4 at 10:12

Hans-Peter Stricker

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Is this a bad moment for a math career?

Awarded Oct 24 at 2:54

Daryl

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Where are the second- (and third-)generation proofs of the classification of finite simple groups up to?

Awarded Oct 23 at 8:33

David Roberts♦

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Eigenvectors of a symmetric positive definite Toeplitz matrix

Awarded Oct 22 at 0:27

Sodalite

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The first eigenvalue of a graph - what does it reflect?

Awarded Oct 20 at 14:17

Seva

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Maxwell's equations and differential forms

Awarded Oct 17 at 7:19

Markus Ulke

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Usefulness of Nash embedding theorem

Awarded Oct 16 at 15:36

Ettore Minguzzi

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A metric for comparing two heatmaps

Awarded Oct 15 at 8:11

cjb

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Theorems with many distinct proofs

Awarded Oct 11 at 0:36

user676464327

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Is the least common multiple sequence $\text{lcm}(1, 2, \dots, n)$ a subset of the highly abundant numbers?

Awarded Oct 8 at 16:25

José Damián Espinosa

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Any good books on numerical methods for ordinary differential equations?

Awarded Oct 8 at 1:17

Zee

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Functions of several complex variables: book recommendations?

Awarded Oct 7 at 5:32

The Mathemagician

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IMO 2017/6 via arithmetic geometry

Awarded Oct 6 at 19:56

Evan Chen

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Nonseparable Hilbert spaces

Awarded Oct 3 at 12:05

truebaran

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Heuristic behind the Fourier-Mukai transform

Awarded Oct 2 at 14:22

Csar Lozano Huerta

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What is the insight of Quillen's proof that all projective modules over a polynomial ring are free?

Awarded Oct 2 at 2:21

Ben Webster

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Why are two "random" vectors in $\mathbb R^n$ approximately orthogonal for large $n$?

Awarded Oct 1 at 16:58

YONGSEEN KIM

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Riemann Zeta Function connection to Quantum Mechanics. [closed]

Awarded Oct 1 at 11:38

Eric Naslund

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Is discrete mathematics mainstream?

Awarded Sep 30 at 3:49

Tomaž Pisanski

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How to tackle the smooth Poincaré conjecture

Awarded Sep 30 at 2:57

Chris Gerig

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Why are planar graphs so exceptional?

Awarded Sep 29 at 18:53

Harrison Brown

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Are there any fields of academic mathematics whose epistemic status as math is controversial within the academic community?

Awarded Sep 29 at 17:06

tparker

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Exact formulas for the partition function?

Awarded Sep 29 at 9:51

Frank Thorne

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List of crowdsourced math projects actively seeking participants

Awarded Sep 29 at 6:12

Terry Tao

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Tools for long-distance collaboration

Awarded Sep 28 at 15:25

Willie Wong

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integral of a "sin-omial" coefficients=binomial

Awarded Sep 28 at 13:51

T. Amdeberhan

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Errata to "Principles of Algebraic Geometry" by Griffiths and Harris

Awarded Sep 28 at 6:19

SpecR

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Why do filtered colimits commute with finite limits?

Awarded Sep 28 at 0:37

Steve Lack

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Intuition behind Alexander duality

Awarded Sep 28 at 0:03

Aaron S

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Never appeared forthcoming papers [closed]

Awarded Sep 27 at 21:50

domenico fiorenza

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Why is integer factoring hard while determining whether an integer is prime easy?

Awarded Sep 26 at 22:45

Craig Feinstein

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Books well-motivated with explicit examples

Awarded Sep 26 at 7:54

Rado

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Fake integers for which the Riemann hypothesis fails?

Awarded Sep 25 at 2:51

Timothy Chow

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Canonical Sheaf of Projective Space

Awarded Sep 23 at 11:01

Rene Schipperus

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Does anyone know a polynomial whose lack of roots can't be proved?

Awarded Sep 16 at 13:38

Akhil Mathew

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calculating Möbius function

Awarded Sep 11 at 21:32

arbitUser1401

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Projection of Borel set from $R^2$ to $R^1$

Awarded Sep 6 at 0:33

Tobias Neukom

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Proving Hodge decomposition without using the theory of elliptic operators?

Awarded Sep 4 at 15:27

Konrad Voelkel

1,9362 gold badges22 silver badges29 bronze badges

When does Cantor-Bernstein hold?

Awarded Sep 3 at 5:27

Randomblue

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Simple examples for the use of spectral sequences

Awarded Sep 1 at 19:39

Hanno

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Does "finitely presented" mean "always finitely presented"? (Answered: Yes!)

Awarded Aug 31 at 1:07

Andrew Critch

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Elementary proof of the equidistribution theorem

Awarded Aug 26 at 2:03

user8761468

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Existence of a zero-sum subset

Awarded Aug 25 at 1:34

Gjergji Zaimi

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Motivating the Casimir element

Awarded Aug 23 at 4:11

Timothy Chow

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What are "good" examples of spin manifolds?

Awarded Aug 19 at 16:32

Otis Chodosh

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Jacobian criterion for smoothness of schemes

Awarded Aug 18 at 14:32

Nicolás

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When is 2 qualitatively different from 3?

Awarded Aug 14 at 13:51

Aryeh Kontorovich

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