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Questions
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14
30
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3
answers
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How do the compact Hausdorff topologies sit in the lattice of all topologies on a set?

5h ago Cameron Buie 31

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61
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41
answers
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What are the most attractive Turing undecidable problems in mathematics?

apr 7 at 4:00 Douglas Ulrich 101●6

 
10
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0
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262
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Can a model of set theory be realized as a Cohen-subset forcing extension in two different ways, with different grounds and different cardinals?

feb 1 at 20:57 Joel David Hamkins 75.2k●7●187●343

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46
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8
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3k
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Can we unify addition and multiplication into one binary operation? To what extent can we find universal binary operations?

dec 3 at 13:00 Mozibur Ullah 806●1●7

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40
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10
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Does War have infinite expected length?

dec 1 at 21:21 tim 1

 
7
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1
answer
277
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Can there be a global linear ordering of the universe without a global well-ordering of the universe?

nov 3 at 18:07 Joel David Hamkins 75.2k●7●187●343

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13
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8
answers
1k
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How should the Math Subject Classification (MSC) be revised or improved?

aug 30 at 17:11 Andreas Blass 32.9k●4●54●109

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15
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0
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484
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Can there be an embedding j:V to L, from the set-theoretic universe V to the constructible universe L, when V not= L?

jul 10 at 3:32 Joel David Hamkins 75.2k●7●187●343

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31
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4
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2k
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Which topological spaces admit a nonstandard metric?

jul 7 at 22:46 HenrikRüping 5,319●5●27

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25
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4
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2k
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Can the symmetric groups on sets of different cardinalities be isomorphic?

apr 23 12 at 13:56 Andreas Blass 32.9k●4●54●109

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