100

Questions

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5

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1

answer

289

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What goes wrong in Easton forcing if we don’t just use regular cardinals?

lo.logic set-theory forcing

nov 20 at 4:11 David Roberts 11.7k●2●18●55

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2

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424

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What is an example of a non-regular, totally path-disconnected Hausdorff space?

at.algebraic-topology gn.general-topology homotopy-theory examples

may 4 10 at 17:38 Jeremy Brazas 1,516●1●5●12

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314

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nerves of crossed complexes, group T-complexes and classifying spaces

ct.category-theory at.algebraic-topology higher-category-theory simplicial-stuff

sep 17 10 at 14:04 Sebastian Thomas 31●2

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Who first came up with the idea of essential/Morita equivalence of internal groupoids/categories?

ct.category-theory internal-groupoids stacks internal-categories reference-request

sep 8 at 20:33 Marta Bunge 96●1●2

5

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2

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435

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Forcing the nonexistence of a certain set

set-theory forcing axiom-of-choice lo.logic ct.category-theory

oct 31 11 at 12:43 Péter Komjáth 3,428●13●19

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2

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464

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Example of a topos that violates countable choice

ct.category-theory topos-theory axiom-of-choice

dec 23 11 at 20:56 Goldstern 5,250●1●12●27

5

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1

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186

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Permutation models with a class-sized group

lo.logic set-theory forcing

dec 16 11 at 19:25 Asaf Karagila 7,198●1●14●44

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0

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126

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Maximal algebraic sub-groupoids

ag.algebraic-geometry internal-categories stacks

feb 7 11 at 9:20 David Roberts 11.7k●2●18●55

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2

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242

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Internal equivalence implies weak equivalence for Frechet Lie groupoids?

dg.differential-geometry ct.category-theory lie-groupoids frechet-manifold

may 4 at 1:22 MathOverflow♦ 1●2●3

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229

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Existence of ‘uniform transformations’ of sequences of rationals (apres Friedman)

lo.logic co.combinatorics

mar 17 12 at 3:29 David Roberts 11.7k●2●18●55