User Mike Shulman

92 votes

8 answers

16k views

Has incorrect notation ever led to a mistaken proof?

asked Aug 9, 2018 at 17:16

48 votes

7 answers

20k views

How to correct an error in a submitted paper?

asked Apr 21, 2010 at 15:50

47 votes

1 answer

2k views

Brown representability for non-connected spaces

asked Aug 16, 2012 at 19:33

46 votes

2 answers

3k views

The formal p-adic numbers

asked Aug 12, 2015 at 23:22

38 votes

3 answers

5k views

Why are profinite topologies important?

asked Dec 15, 2010 at 4:14

36 votes

3 answers

2k views

Internal logic of the topos of simplicial sets

asked Mar 11, 2014 at 0:43

32 votes

1 answer

2k views

Can ZFC → NBG be iterated?

asked Jan 5, 2011 at 22:44

30 votes

6 answers

3k views

Mathematics without the principle of unique choice

asked Jun 5, 2018 at 4:34

28 votes

2 answers

4k views

What does an etale topos classify?

asked Dec 8, 2010 at 23:31

26 votes

1 answer

780 views

Finite limits in the category of smooth manifolds?

asked Apr 6, 2014 at 4:09

24 votes

2 answers

1k views

Can equivalences be strictified to isomorphisms?

asked Jun 5, 2010 at 23:07

24 votes

1 answer

1k views

Small complete categories in a Grothendieck topos

asked Oct 24, 2010 at 21:16

24 votes

1 answer

1k views

What is $\infty^6$?

asked Jun 5, 2015 at 15:40

24 votes

10 answers

4k views

Why localize spaces with respect to homology?

asked Jul 7, 2014 at 23:55

23 votes

1 answer

3k views

When does collection imply replacement?

asked Jan 21, 2010 at 23:13

23 votes

8 answers

3k views

How many proofs that $\pi_n(S^n)=\mathbb{Z}$ are there?

asked Feb 8, 2013 at 0:27

23 votes

5 answers

1k views

Sheafification via hypercovers

asked Mar 12, 2012 at 8:13

22 votes

1 answer

2k views

Condensed vs pyknotic vs consequential

asked Feb 28, 2023 at 20:09

21 votes

1 answer

1k views

Logical endofunctors of Set?

asked Nov 4, 2009 at 3:25

21 votes

3 answers

3k views

Approximate intermediate value theorem in pure constructive mathematics

asked Oct 25, 2016 at 17:34

20 votes

3 answers

911 views

Brouwer's theorem for the Cauchy reals

asked Aug 28, 2015 at 3:04

20 votes

2 answers

740 views

Limitations on model-categorical presentations

asked Apr 29, 2012 at 17:18

20 votes

8 answers

2k views

Should a theorem be numbered by where it is first stated or where it is proven?

asked May 20, 2014 at 16:38

19 votes

2 answers

2k views

Internal categories in simplicial sets

asked Dec 23, 2012 at 15:04

19 votes

3 answers

1k views

Set-theoretic forcing over sites?

asked Jan 30, 2010 at 16:39

19 votes

1 answer

1k views

When is a reflective subcategory of a topos a topos?

asked Dec 10, 2011 at 22:08

18 votes

1 answer

1k views

Can Vopenka's principle be violated definably?

asked Nov 10, 2010 at 21:14

17 votes

4 answers

2k views

Degeneracies for semi-simplicial Kan complexes

asked Mar 7, 2011 at 11:47

17 votes

4 answers

2k views

Does the classification diagram localize a category with weak equivalences?

asked Apr 2, 2012 at 18:05

17 votes

2 answers

1k views

Loop space of a category

asked Nov 26, 2012 at 16:41

Stack Exchange Network

154 Questions

Has incorrect notation ever led to a mistaken proof?

How to correct an error in a submitted paper?

Brown representability for non-connected spaces

The formal p-adic numbers

Why are profinite topologies important?

Internal logic of the topos of simplicial sets

Can ZFC → NBG be iterated?

Mathematics without the principle of unique choice

What does an etale topos classify?

Finite limits in the category of smooth manifolds?

Can equivalences be strictified to isomorphisms?

Small complete categories in a Grothendieck topos

What is $\infty^6$?

Why localize spaces with respect to homology?

When does collection imply replacement?

How many proofs that $\pi_n(S^n)=\mathbb{Z}$ are there?

Sheafification via hypercovers

Condensed vs pyknotic vs consequential

Logical endofunctors of Set?

Approximate intermediate value theorem in pure constructive mathematics

Brouwer's theorem for the Cauchy reals

Limitations on model-categorical presentations

Should a theorem be numbered by where it is first stated or where it is proven?

Internal categories in simplicial sets

Set-theoretic forcing over sites?

When is a reflective subcategory of a topos a topos?

Can Vopenka's principle be violated definably?

Degeneracies for semi-simplicial Kan complexes

Does the classification diagram localize a category with weak equivalences?

Loop space of a category