User Pace Nielsen - MathOverflow

57 votes

7 answers

10k views

Zorn's lemma: old friend or historical relic?

asked Dec 11, 2022 at 17:50

35 votes

6 answers

4k views

Is there a metamathematical $V$?

asked Feb 3, 2021 at 22:36

32 votes

6 answers

6k views

How do we recognize an integer inside the rationals?

asked Mar 30, 2010 at 15:24

31 votes

10 answers

5k views

Defining the standard model of PA so that a space alien could understand

asked May 22, 2019 at 21:04

31 votes

4 answers

5k views

How dangerous are set-size assumptions?

asked Jun 19, 2019 at 18:08

28 votes

2 answers

957 views

$A^2$ is isomorphic to $A^{(\omega)}$, but not $A$

asked Aug 16, 2022 at 19:39

27 votes

4 answers

12k views

Is there an elementary way to find the integer solutions to $x^2-y^3=1$?

asked Sep 22, 2010 at 0:04

26 votes

2 answers

2k views

What do you do if you believe a problem is undecidable?

asked Feb 6, 2015 at 16:55

23 votes

5 answers

2k views

Platonic Truth and 1st Order Predicate Logic

asked Dec 27, 2016 at 17:36

17 votes

1 answer

2k views

The axiom of choice as a consequence of a stronger semantics?

asked Jul 10, 2017 at 19:20

17 votes

0 answers

668 views

Are there more true statements than false ones?

asked Jul 31, 2023 at 3:38

15 votes

1 answer

885 views

Spelling König's Lemma

asked Aug 29, 2019 at 20:27

14 votes

3 answers

2k views

Tarski's truth theorem — semantic or syntactic?

asked Apr 27, 2020 at 17:24

14 votes

1 answer

925 views

Papers with a large number of coauthors

asked Jun 17, 2020 at 21:18

14 votes

2 answers

1k views

MathSciNet Reference Fixes

asked Sep 26, 2017 at 19:59

14 votes

1 answer

2k views

Character sums over prime arguments

asked Jun 9, 2010 at 21:19

12 votes

2 answers

1k views

Density in van der Waerden's theorem

asked Jan 13, 2012 at 18:56

11 votes

2 answers

1k views

Set theory bootstrapping

asked Jul 30, 2018 at 4:24

11 votes

2 answers

689 views

Identifying a group without 2-torsion

asked May 24, 2017 at 17:50

11 votes

4 answers

2k views

When is it okay to intersect infinite families of proper classes?

asked Jan 30, 2019 at 20:14

11 votes

2 answers

529 views

Odd degree polynomials over fields

asked Jan 28 at 0:09

10 votes

0 answers

1k views

Dimensions of dual vector spaces

asked Jan 27, 2016 at 20:19

10 votes

3 answers

728 views

Freiling's Axiom of Symmetry Concretized

asked Mar 25, 2015 at 21:05

10 votes

2 answers

610 views

A back and forth Euclidean algorithm over the integers--does it have bounded length?

asked Nov 10, 2014 at 17:40

10 votes

1 answer

280 views

Matrix ring isomorphisms of different sizes

asked Feb 23, 2024 at 13:54

9 votes

3 answers

3k views

Russell's paradox as understood by current set theorists

asked Sep 16, 2020 at 21:59

9 votes

1 answer

1k views

First isomorphism theorem for sets?

asked Sep 23, 2021 at 21:30

9 votes

1 answer

788 views

Hensel's lemma, Bezout's identity, and the integers

asked Oct 21, 2021 at 17:05

9 votes

4 answers

625 views

Basic Algebraic Applications of Stationary Sets?

asked Aug 30, 2017 at 14:30

8 votes

3 answers

909 views

Does a left basis imply a right basis, without AC?

asked Dec 7, 2014 at 4:50

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74 Questions

Zorn's lemma: old friend or historical relic?

Is there a metamathematical $V$?

How do we recognize an integer inside the rationals?

Defining the standard model of PA so that a space alien could understand

How dangerous are set-size assumptions?

$A^2$ is isomorphic to $A^{(\omega)}$, but not $A$

Is there an elementary way to find the integer solutions to $x^2-y^3=1$?

What do you do if you believe a problem is undecidable?

Platonic Truth and 1st Order Predicate Logic

The axiom of choice as a consequence of a stronger semantics?

Are there more true statements than false ones?

Spelling König's Lemma

Tarski's truth theorem — semantic or syntactic?

Papers with a large number of coauthors

MathSciNet Reference Fixes

Character sums over prime arguments

Density in van der Waerden's theorem

Set theory bootstrapping

Identifying a group without 2-torsion

When is it okay to intersect infinite families of proper classes?

Odd degree polynomials over fields

Dimensions of dual vector spaces

Freiling's Axiom of Symmetry Concretized

A back and forth Euclidean algorithm over the integers--does it have bounded length?

Matrix ring isomorphisms of different sizes

Russell's paradox as understood by current set theorists

First isomorphism theorem for sets?

Hensel's lemma, Bezout's identity, and the integers

Basic Algebraic Applications of Stationary Sets?

Does a left basis imply a right basis, without AC?