100

Questions

votes newest views recent

1

6

votes

1

answer

199

views

Detecting homotopy nontriviality of an element in a torsion homotopy group

gt.geometric-topology homotopy-theory homotopy-groups-of-sphere

apr 13 at 3:48 Allen Hatcher 7,169●2●26●35

3

votes

1

answer

298

views

How much of ZFC do I need to construct this cofinal, order-preserving class function?

lo.logic set-theory axiom-of-choice transfinite-induction

apr 13 at 21:43 Joel David Hamkins 74.7k●7●187●343

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4

votes

0

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109

views

Extracting internal sites of definition

ct.category-theory topos-theory geometric-morphism

apr 10 at 7:49 David Roberts 11.7k●2●18●55

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7

votes

1

answer

616

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How many proofs of the Weil conjectures are there?

ag.algebraic-geometry weil-conjectures nt.number-theory soft-question

mar 21 at 22:11 SM 371●2

1

5

votes

1

answer

293

views

First mention of the fundamental bigroupoid of a space?

ho.history-overview ct.category-theory homotopy-theory

mar 1 at 20:36 Ronnie Brown 5,209●17●20

1

6

votes

0

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163

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What is the state of the art in 4-manfold 2-types?

gt.geometric-topology four-manifolds homotopy-theory reference-request

feb 1 at 6:10 David Roberts 11.7k●2●18●55

1

6

votes

2

answers

321

views

From the product lemma to to a result about powersets

lo.logic set-theory forcing reference-request

jan 22 at 4:02 David Roberts 11.7k●2●18●55

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13

votes

3

answers

541

views

Characterising categories of vector spaces

ct.category-theory homological-algebra ra.rings-and-algebras

jan 7 at 19:39 John Baez 1,730●7●20

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13

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0

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291

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Relative consistency of ETCS over the theory of a well-pointed topos with NNO

ct.category-theory lo.logic set-theory

jan 3 at 1:18 David Roberts 11.7k●2●18●55

3

votes

1

answer

234

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Can we weaken GCH in this class forcing?

lo.logic set-theory forcing

dec 21 at 13:44 François G. Dorais♦ 22.3k●2●48●113