Mathieu Baillif's user avatar
Mathieu Baillif's user avatar
Mathieu Baillif's user avatar
Mathieu Baillif
  • Member for 11 years, 3 months
  • Last seen this week
  • Switzerland
14 votes
3 answers
1k views

Axiom of choice for sets of finite sets

10 votes
1 answer
880 views

A proof without derivatives that a real polynomial of degree $n$ has at most $n-1$ local extrema

10 votes
1 answer
511 views

What's the volume of $\{x\in[0,1]^n|\sum x_i\le t\}$ for real $t$?

8 votes
0 answers
395 views

Is the product of a discretely Lindelöf space with [0,1] discretely Lindelöf ?

8 votes
0 answers
495 views

Is there in ZFC a topological space which is normal, ccc, countably compact, first countable and non-compact?

8 votes
0 answers
120 views

Is there a normal non-collectionwise Hausdorff manifold?

6 votes
0 answers
107 views

How to call a point in a space having the property that there is essentially one $\omega$-sequence converging to it?

4 votes
1 answer
146 views

Given $f$ from the cylinder $C$ to the interval constant on one boundary, is there a $r:C\to C$ constant on a boundary with $f\circ r = f$?

3 votes
0 answers
72 views

Which spaces are still Lindelöf after forcing with a Suslin tree?

2 votes
2 answers
166 views

Does any subset of $\beta\omega$ of cardinality $\mathfrak{c}$ have a weak P-point in its closure?

1 vote
0 answers
318 views

Type I subspaces of the Stone Cech compactification of $\omega$