User Danielle Ulrich

16 votes

Accepted

Can an ultrapower be undone by forcing?

answered Dec 26, 2015 at 22:41

16 votes

Is there a theorem whose only known proof uses "$A$ or not $A$" for undecidable $A$

answered Nov 19, 2016 at 19:45

9 votes

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Which reals are "hyperarithmetic modulo ordinals"?

answered Aug 29, 2016 at 23:55

8 votes

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Elementary extensions of direct product

answered Feb 11, 2017 at 19:20

8 votes

Examples of set theory problems which are solved using methods outside of logic

answered Aug 25, 2018 at 8:55

8 votes

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A new cardinal characteristic of the continuum?

answered Aug 31, 2018 at 18:26

7 votes

On structures that are not submitted to compatibility conditions

answered Apr 27, 2017 at 0:51

6 votes

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Models with few types in infinitary logics

answered Oct 21, 2017 at 19:27

5 votes

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When are generic models not too wild?

answered Jun 1, 2016 at 20:57

4 votes

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How many elementary embeddings can there be?

answered Dec 5, 2016 at 15:35

4 votes

Is there a class of mathematical structures with non-isomorphic natural representations as a standard Borel space?

answered Apr 5, 2016 at 21:52

4 votes

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Perfectly transversable theories

answered Mar 26, 2017 at 18:37

3 votes

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Consistency of Weak Diamond with a Weak Version of Martin's Axiom

answered Oct 14, 2014 at 3:54

2 votes

What are the most attractive Turing undecidable problems in mathematics?

answered Apr 7, 2013 at 3:52

2 votes

Problem understanding a passage of the proof of $\mathfrak{p}=\mathfrak{t}$ involving forcing

answered Sep 1, 2018 at 19:56

2 votes

Accepted

Theories with the infinitary Vopenka property

answered Jan 28, 2017 at 5:13

1 vote

A "Completion" of $ZFC^-$

answered Dec 9, 2016 at 17:27

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17 Answers

Can an ultrapower be undone by forcing?

Is there a theorem whose only known proof uses "$A$ or not $A$" for undecidable $A$

Which reals are "hyperarithmetic modulo ordinals"?

Elementary extensions of direct product

Examples of set theory problems which are solved using methods outside of logic

A new cardinal characteristic of the continuum?

On structures that are not submitted to compatibility conditions

Models with few types in infinitary logics

When are generic models not too wild?

How many elementary embeddings can there be?

Is there a class of mathematical structures with non-isomorphic natural representations as a standard Borel space?

Perfectly transversable theories

Consistency of Weak Diamond with a Weak Version of Martin's Axiom

What are the most attractive Turing undecidable problems in mathematics?

Problem understanding a passage of the proof of $\mathfrak{p}=\mathfrak{t}$ involving forcing

Theories with the infinitary Vopenka property

A "Completion" of $ZFC^-$