User Dennis

20 votes

7 answers

5k views

In what sense of "structure" do group homomorphisms "preserve structure"?

asked Feb 21, 2015 at 1:31

18 votes

2 answers

690 views

What lessons have mathematicians drawn from the existence of non-standard models?

asked Apr 8, 2013 at 4:56

13 votes

1 answer

2k views

Why wouldn't someone accept Gentzen's consistency proof?

asked Oct 15, 2014 at 17:31

10 votes

1 answer

498 views

Do second-order categoricity proofs require a background concept of set?

asked Jan 3, 2014 at 19:44

9 votes

1 answer

286 views

Do metatheoretic results carry between mutually interpretable theories?

asked Dec 30, 2013 at 3:12

9 votes

2 answers

1k views

Henkin vs. "Full" Semantics for Second-order Logic and Multi-Sorted First Order Interpretations

asked Jun 14, 2013 at 16:05

9 votes

1 answer

1k views

Why isn't second-order ZFC categorical?

asked Mar 30, 2015 at 15:03

8 votes

1 answer

326 views

The Logic of Satisfiability?

asked Feb 28, 2013 at 3:08

7 votes

1 answer

204 views

Do the ZF-provable forcing principles differ from the ZFC-provable forcing principles?

asked Nov 27, 2015 at 20:31

6 votes

2 answers

2k views

Differences between pure and impure set theory?

asked Jan 3, 2013 at 6:31

6 votes

1 answer

174 views

Are there other, non-model theoretic, accounts of semantic validity?

asked Jun 14, 2013 at 20:51

6 votes

3 answers

451 views

Applications of Category Theory Outside of Mathematics (the discipline)

asked Jul 30, 2013 at 6:45

6 votes

3 answers

908 views

Are the arrows of category theory (in general) "intensional"?

asked Apr 24, 2017 at 0:28

5 votes

1 answer

545 views

Are there such things as non-extensional set theories?

asked Nov 1, 2013 at 17:23

5 votes

1 answer

259 views

Are the non-standard models of classical analysis the standard models of non-standard analysis?

asked Mar 22, 2013 at 8:03

5 votes

1 answer

312 views

Model theory for intuitionistic predicate logic: a non-empty domain?

asked Dec 30, 2012 at 19:17

5 votes

2 answers

117 views

Identity of Initial Elements in a Category

asked Jul 28, 2013 at 22:35

5 votes

0 answers

231 views

Interpretation of impure set theory within pure set theory?

asked Jan 8, 2013 at 20:40

5 votes

1 answer

126 views

Forcing names, parameters in definitions, and the Iterative Conception of Set

asked Dec 18, 2015 at 4:47

5 votes

2 answers

1k views

What are the leading alternative foundations for mathematics?

asked Nov 10, 2014 at 4:21

4 votes

2 answers

142 views

What are the uses of cross-theoretic identifications within mathematics?

asked Mar 12, 2015 at 22:16

4 votes

1 answer

329 views

Failures of categoricity not related to size?

asked Mar 25, 2015 at 19:20

4 votes

1 answer

108 views

Finite axiomatizability of theories in infinitary logic?

asked Jan 19, 2018 at 5:29

3 votes

1 answer

227 views

Are identity morphisms on the underlying quiver of a category loops or empty paths?

asked May 20, 2017 at 21:32

3 votes

0 answers

65 views

Locally Small Categories in a 3 sorted Theory of Collections

asked Jun 18, 2017 at 19:06

3 votes

1 answer

330 views

Do non-standard models of arithmetic add properties to what are "intuitively" their standard numbers?

asked Jun 21, 2017 at 21:21

3 votes

1 answer

1k views

Under what conditions does an axiomatic proof system have a natural deduction equivalent?

asked Aug 17, 2017 at 21:52

3 votes

3 answers

509 views

What is the meaning of "uncountably infinite" within countable models of set theory?

asked Feb 11, 2015 at 22:11

3 votes

1 answer

109 views

In what sense does forcing increase the width of a set-theoretic hierarchy?

asked Feb 6, 2016 at 21:34

2 votes

1 answer

86 views

In what sense do the global elements of a poset correspond to the elements of its underlying set?

asked Apr 17, 2017 at 1:43

Stack Exchange Network

54 Questions

In what sense of "structure" do group homomorphisms "preserve structure"?

What lessons have mathematicians drawn from the existence of non-standard models?

Why wouldn't someone accept Gentzen's consistency proof?

Do second-order categoricity proofs require a background concept of set?

Do metatheoretic results carry between mutually interpretable theories?

Henkin vs. "Full" Semantics for Second-order Logic and Multi-Sorted First Order Interpretations

Why isn't second-order ZFC categorical?

The Logic of Satisfiability?

Do the ZF-provable forcing principles differ from the ZFC-provable forcing principles?

Differences between pure and impure set theory?

Are there other, non-model theoretic, accounts of semantic validity?

Applications of Category Theory Outside of Mathematics (the discipline)

Are the arrows of category theory (in general) "intensional"?

Are there such things as non-extensional set theories?

Are the non-standard models of classical analysis the standard models of non-standard analysis?

Model theory for intuitionistic predicate logic: a non-empty domain?

Identity of Initial Elements in a Category

Interpretation of impure set theory within pure set theory?

Forcing names, parameters in definitions, and the Iterative Conception of Set

What are the leading alternative foundations for mathematics?

What are the uses of cross-theoretic identifications within mathematics?

Failures of categoricity not related to size?

Finite axiomatizability of theories in infinitary logic?

Are identity morphisms on the underlying quiver of a category loops or empty paths?

Locally Small Categories in a 3 sorted Theory of Collections

Do non-standard models of arithmetic add properties to what are "intuitively" their standard numbers?

Under what conditions does an axiomatic proof system have a natural deduction equivalent?

What is the meaning of "uncountably infinite" within countable models of set theory?

In what sense does forcing increase the width of a set-theoretic hierarchy?

In what sense do the global elements of a poset correspond to the elements of its underlying set?