User Holo

12 votes

Theorems with many distinct proofs

answered Aug 12, 2021 at 16:02

11 votes

Simpler proofs using the axiom of choice

answered Jan 20, 2023 at 16:17

8 votes

Accepted

Large cardinal near inconsistencies

answered Jun 26, 2023 at 21:28

7 votes

Is the union of two conservative extensions of a theory conservative?

answered Apr 14, 2023 at 15:41

6 votes

Accepted

Is ZF + Def a conservative extension of ZFC+HOD? If not, what are counter-examples?

answered Jun 27, 2023 at 19:44

6 votes

Why we need to choose direction in the "marry the arrows" algorithm?

answered Nov 10, 2022 at 12:24

6 votes

Can we iteratively reflect on self elementary embeddable stages of the cumulative hierarchy?

answered Jan 18, 2023 at 17:49

5 votes

Accepted

Does n-well ordered choice schema imply the axiom of choice?

answered Feb 22, 2023 at 21:42

4 votes

Accepted

Does cardinal definable choice imply AC?

answered Feb 27, 2023 at 17:13

4 votes

Accepted

Automorphisms of vector spaces and the complex numbers without choice

answered Mar 1, 2023 at 20:16

3 votes

Accepted

Can we iteratively reflect on self elementary embeddable stages of the cumulative hierarchy?

answered Jan 19, 2023 at 13:42

2 votes

Accepted

Need proof on a model being elementarily equivalent but non-isomorphic

answered Mar 6, 2023 at 18:31

2 votes

Accepted

Is the chromatic number of hypergraphs downward continuous?

answered May 21, 2023 at 17:05

2 votes

How do these two principles of Foundation written in $\mathcal L_{\omega_1,\omega}$ compare?

answered Jun 14, 2023 at 11:58

2 votes

Accepted

Which fragment of ZF does the class of all hereditarily predicatively definable sets capture?

answered Feb 15, 2023 at 10:39

0 votes

Can having no more than countably many classes, be inferred from, having every class being countable?

answered Dec 27, 2022 at 22:28

Stack Exchange Network

16 Answers

Theorems with many distinct proofs

Simpler proofs using the axiom of choice

Large cardinal near inconsistencies

Is the union of two conservative extensions of a theory conservative?

Is ZF + Def a conservative extension of ZFC+HOD? If not, what are counter-examples?

Why we need to choose direction in the "marry the arrows" algorithm?

Can we iteratively reflect on self elementary embeddable stages of the cumulative hierarchy?

Does n-well ordered choice schema imply the axiom of choice?

Does cardinal definable choice imply AC?

Automorphisms of vector spaces and the complex numbers without choice

Can we iteratively reflect on self elementary embeddable stages of the cumulative hierarchy?

Need proof on a model being elementarily equivalent but non-isomorphic

Is the chromatic number of hypergraphs downward continuous?

How do these two principles of Foundation written in $\mathcal L_{\omega_1,\omega}$ compare?

Which fragment of ZF does the class of all hereditarily predicatively definable sets capture?

Can having no more than countably many classes, be inferred from, having every class being countable?