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What's the earliest result (outside of logic) that cannot be proven constructively?

Awarded Feb 23 at 1:41

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Could someone explain the proof of this formula clearly? I got the wrong values for spanning trees with this formula and with Cayley's formula

Awarded Feb 22 at 18:30

Noxious Reptile

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Are there times when replacement is "more natural" than collection?

Awarded Feb 22 at 14:18

Noah Schweber

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Prove these are not surface groups

Awarded Feb 22 at 13:00

Linda T

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When can a function defined on $[a, b] \cup [b, c]$ be constructively extended to a function defined on $[a, c]$?

Awarded Feb 22 at 10:52

Christopher King

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Asymptotics of a strange oscillatory function

Awarded Feb 22 at 8:18

Satan's Minion

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Is it true that $\det\big[\sin 2\pi\frac{(j-k)^2}p\big]_{1\le j,k\le p-1}=-\frac{p^{(p-1)/2}}{2^{p-1}}$ for each prime $p\equiv3\pmod4$?

Awarded Feb 22 at 8:18

Zhi-Wei Sun

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Which closed subsets $Y$ of a compact space $X$ admit a linear extensor $C(Y)\to C(X)$?

Awarded Feb 22 at 8:07

Pietro Majer

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Why do we say IndCoh(X) is analogous to the set of distributions on X?

Awarded Feb 22 at 3:35

JustLikeNumberTheory

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Relationship between fragments of the axiom of choice and the dependent choice principles

Awarded Feb 21 at 12:35

Victoria Gitman

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How to optimally bet on a biased coin?

Awarded Feb 20 at 1:42

Nate River

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System of quadratic equations

Awarded Feb 19 at 21:36

meie73

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Isomorphic finite fields of a skew field

Awarded Feb 19 at 16:55

Alborz Azarang

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Is a Borel image of a Polish space analytic?

Awarded Feb 19 at 15:12

Taras Banakh

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On the classification of second-countable Stone spaces

Awarded Feb 19 at 13:27

Tim Campion♦

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On the equation $9x^3+y^3=z^2+3$

Awarded Feb 19 at 10:41

Bogdan Grechuk

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Changing the cofinality of a regular cardinal without collapsing any cardinals?

Awarded Feb 19 at 5:32

user2925716

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Is 100 the only Leyland number that is a square?

Awarded Feb 19 at 1:18

don bright

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Does anyone use non-sober topological spaces?

Awarded Feb 18 at 21:43

Harry Gindi

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Do sparse DAGs can have large min-cuts?

Awarded Feb 18 at 6:48

Stasys

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What is this equivalence relation on topological spaces: there are bijective continuous maps in both directions

Awarded Feb 17 at 2:28

M. Winter

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Motivation and physical interpretation of the Laplace transform

Awarded Feb 15 at 22:16

AlpinistKitten

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Is every polynomial of the form $2x^{2n} -x^n +1$ irreducible over $\mathbb{Z}$?

Awarded Feb 15 at 21:19

JoshuaZ

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Is there a definition of an $\infty$-groupoid in HoTT whose terms are $n$-manifolds and whose higher morphisms are diffeomorphisms/isotopies/etc?

Awarded Feb 15 at 15:41

Andy Manion

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Does the Hodge star operator determine the metric?

Awarded Feb 15 at 5:05

Zhiqiang

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Relative cocompletion of a category

Awarded Feb 15 at 4:05

Adrien

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Guaranteed correct digits of elementary expressions

Awarded Feb 14 at 22:06

rosan98

3618 bronze badges

Undefinable inner model

Awarded Feb 14 at 13:40

new account

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A weak form of countable choice

Awarded Feb 14 at 13:31

Mark Saving

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Richardson varieties over finite fields

Awarded Feb 14 at 8:16

Steven Sam

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How to get to the earliest time zone?

Awarded Feb 14 at 4:58

Nate River

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Slick proofs using the Henstock–Kurzweil integral?

Awarded Feb 14 at 2:06

Timothy Chow

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Upper bound Hölder norm of the solution to the non-linear PDE $\partial_t u (t, x) = \Delta_x \{ |\sigma (u (t, x))|^2 u(t, x) \}$

Awarded Feb 13 at 12:16

Akira

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Bundle-to-function correspondence

Awarded Feb 13 at 3:56

David Spivak

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Understanding absolute Galois group from its representations

Awarded Feb 13 at 2:17

Uzu Lim

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Classification of singularities of plane curves of fixed degree (reference request)

Awarded Feb 12 at 21:18

Ben

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What mathematical problems can be attacked using DeepMind's recent mathematical breakthroughs?

Awarded Feb 12 at 0:57

Ryan Hendricks

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Proofs of Serre's theorem on simply-connected finite CW complexes

Awarded Feb 12 at 0:17

homotopy-enthusiast

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Hall-Littlewood functions and functions on the nilpotent cone

Awarded Feb 11 at 17:31

Yuji Tachikawa

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English translation of Wilhelm Killing's 1889 paper

Awarded Feb 11 at 15:09

Zurab Silagadze

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Suggestions and feature requests for the design of a font for math articles/books

Awarded Feb 11 at 8:19

Emily

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Are there workable algebraic geometry approaches for the pentagon equation?

Awarded Feb 11 at 1:06

Sebastien Palcoux

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Elementary equivalence between $n\mapsto n+1$ and its inverse on the Stone-Čech remainder?

Awarded Feb 10 at 6:21

YCor

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How to write mathematics without typing?

Awarded Feb 9 at 21:48

Anonymous

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Who proved the motivic 6-functor formalism?

Awarded Feb 9 at 21:48

Ola Sande

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Primality of a number of more than 50k digits

Awarded Feb 9 at 21:17

D J Sims

Primality of a number of more than 50k digits

Awarded Feb 9 at 20:06

Uk rain troll

Can you deduce the correspondence between 2D oriented TQFTs and commutative Frobenius algebras from the (framed) Cobordism Hypothesis?

Awarded Feb 9 at 17:25

Santiago Pareja Pérez

1136 bronze badges

Does anyone recognize this condition on a Riemannian metric on a vector space?

Awarded Feb 9 at 9:08

Terry Tao

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Why Kleisli Markov categories and not the Eilenberg-Moore categories of the associated monads

Awarded Feb 8 at 10:11

Q.Faustus

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Is there a program implementation for generating all non-isomorphic graphs with a given degree sequence?

Awarded Feb 8 at 5:32

L.C. Zhang

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Is there a theory between HA and PA that doesn't have Markov's rule?

Awarded Feb 7 at 19:40

Christopher King

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Tips for reading arXiv papers in mathematics

Awarded Feb 7 at 17:18

Shaun

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Arithmetic product of symmetric functions: why is it integral?

Awarded Feb 7 at 1:10

darij grinberg

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Chevalley Groups over an arbitrary ring.

Awarded Feb 6 at 22:47

M.B

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Scrambling a “Connections” grid

Awarded Feb 6 at 20:15

James Propp

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Why Huber rings?

Awarded Feb 6 at 14:47

Alex Mathers

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Convexity and Lipschitz continuity

Awarded Feb 6 at 12:15

Piotr Hajlasz

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What was the "stormy discussion" about differential Galois theory at IHES?

Awarded Feb 6 at 7:18

Phil Harmsworth

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Cantor-Bernstein with "weakly injective" functions

Awarded Feb 5 at 21:47

Dominic van der Zypen

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