User Andreas Blass

12 votes

Accepted

Given a cardinal k, what's the biggest dense linear order with a dense subset of size k?

answered Dec 5, 2010 at 0:34

18 votes

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Proper classes and their consequences

answered Dec 4, 2010 at 22:38

33 votes

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Is P=NP relevant to finding proofs of everyday mathematical propositions?

answered Dec 2, 2010 at 18:51

2 votes

Accepted

Are these systems of linear equations always solvable

answered Nov 30, 2010 at 14:48

3 votes

Cryptomorphisms

answered Nov 26, 2010 at 17:29

5 votes

"Let $x \in A$", beginning a proof of "$\forall x \in A$ ...", if A were empty

answered Nov 23, 2010 at 13:44

3 votes

Accepted

Which properties of ultrafilters on countable sets hold for filters in general?

answered Nov 21, 2010 at 23:00

24 votes

How to introduce notions of flat, projective and free modules?

answered Nov 18, 2010 at 22:59

15 votes

Explicit Hamel basis of real numbers

answered Nov 14, 2010 at 23:05

8 votes

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Do filters complementive to a given filter form a complete lattice?

answered Nov 11, 2010 at 2:48

2 votes

Accepted

Condition for Uniqueness of Measures

answered Nov 10, 2010 at 22:25

12 votes

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If $K$ and $L$ are compact convex sets with smooth boundary, does their union have piecewise-smooth boundary?

answered Nov 10, 2010 at 17:16

15 votes

What is the idea behind stationary sets?

answered Nov 9, 2010 at 18:23

10 votes

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Compactness Theorem for First Order Logic

answered Nov 9, 2010 at 23:47

8 votes

Accepted

Choice Function on the Powerset of the Reals

answered Nov 8, 2010 at 16:40

17 votes

Aut(G) = $C_3$, G = ?

answered Nov 7, 2010 at 22:39

13 votes

Pseudonyms of famous mathematicians

answered Nov 7, 2010 at 21:25

27 votes

Are there more connected or disconnected graphs on $n$ vertices?

answered Nov 5, 2010 at 1:28

39 votes

Arguments against large cardinals

answered Oct 30, 2010 at 15:12

7 votes

An ultrafilter and a partition

answered Oct 29, 2010 at 6:02

41 votes

Is there a measure zero set which isn't meagre?

answered Oct 25, 2010 at 12:34

2 votes

Accepted

Existence of enough projectives in the category of sets

answered Oct 23, 2010 at 18:54

2 votes

A Theory of 3-connected graphs

answered Oct 22, 2010 at 15:40

5 votes

Accepted

Do functions defined on global elements give rise to arrows in a well-pointed topos?

answered Oct 14, 2010 at 22:29

35 votes

Accepted

Does constructing non-measurable sets require the axiom of choice?

answered Oct 14, 2010 at 21:55

4 votes

non-isomorphic objects with no known nontrivial distinguishing invariants

answered Oct 8, 2010 at 13:13

3 votes

Nonmetrizable uniformities with metrizable topologies

answered Oct 8, 2010 at 12:38

3 votes

Statistics for Second order properties of Random graphs

answered Oct 7, 2010 at 21:36

7 votes

Commutative algebras and Gamma-modules

answered Oct 7, 2010 at 21:22

7 votes

Theorems true but wrong.

answered Oct 5, 2010 at 13:43

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785 Answers

Given a cardinal k, what's the biggest dense linear order with a dense subset of size k?

Proper classes and their consequences

Is P=NP relevant to finding proofs of everyday mathematical propositions?

Are these systems of linear equations always solvable

Cryptomorphisms

"Let $x \in A$", beginning a proof of "$\forall x \in A$ ...", if A were empty

Which properties of ultrafilters on countable sets hold for filters in general?

How to introduce notions of flat, projective and free modules?

Explicit Hamel basis of real numbers

Do filters complementive to a given filter form a complete lattice?

Condition for Uniqueness of Measures

If $K$ and $L$ are compact convex sets with smooth boundary, does their union have piecewise-smooth boundary?

What is the idea behind stationary sets?

Compactness Theorem for First Order Logic

Choice Function on the Powerset of the Reals

Aut(G) = $C_3$, G = ?

Pseudonyms of famous mathematicians

Are there more connected or disconnected graphs on $n$ vertices?

Arguments against large cardinals

An ultrafilter and a partition

Is there a measure zero set which isn't meagre?

Existence of enough projectives in the category of sets

A Theory of 3-connected graphs

Do functions defined on global elements give rise to arrows in a well-pointed topos?

Does constructing non-measurable sets require the axiom of choice?

non-isomorphic objects with no known nontrivial distinguishing invariants

Nonmetrizable uniformities with metrizable topologies

Statistics for Second order properties of Random graphs

Commutative algebras and Gamma-modules

Theorems true but wrong.