User Dan Rust

156 votes

3 answers

19k views

Slice of pizza with no crust

asked Sep 1, 2013 at 18:38

98 votes

2 answers

2k views

Geometric way to view the truncated braid groups?

asked Jun 3, 2013 at 15:48

37 votes

2 answers

2k views

Homeomorphic to the disk implies existence of fixed point common to all isometries?

asked Sep 20, 2013 at 18:39

27 votes

1 answer

2k views

Examples of falsified (or currently open) longstanding conjectures leading to large bodies of incorrect results.

asked Mar 31, 2013 at 17:47

26 votes

1 answer

8k views

Does taking the direct limit of chain complexes commute with taking homology?

asked May 24, 2013 at 16:03

13 votes

1 answer

559 views

Applications of TQFTs beyond physics

asked Nov 30, 2013 at 1:14

13 votes

2 answers

5k views

Equivalences and isomorphisms of short exact sequences

asked Apr 4, 2013 at 23:05

13 votes

1 answer

748 views

Can the n-string sphere braid group embed in to the (n+1)-string sphere braid group?

asked Apr 25, 2012 at 15:22

6 votes

2 answers

502 views

Properties of the Category of topological spaces with $n$ basepoints.

asked Mar 11, 2013 at 13:42

5 votes

3 answers

1k views

Showing that the loopspace $\Omega S^{\infty}$ is homotopic to $S^{\infty}$.

asked Apr 13, 2012 at 20:37

5 votes

1 answer

179 views

Higher dimensional analogue of the correspondence between $2$d TQFTs and Frobenius algebras?

asked Jan 1, 2014 at 19:17

5 votes

0 answers

398 views

Cohomology of the pullback of a fiber bundle over the torus (generalised Eilenberg-Moore spectral sequence?)

asked Jul 26, 2013 at 13:35

5 votes

1 answer

236 views

Applying Khovanov homology to two different non-trivial diagrams of the unknot

asked Mar 3, 2014 at 16:39

4 votes

0 answers

80 views

Finite strings of integers from $\{1,1,2,2,\ldots,n,n\}$ such that there are $k$ elements between the two $k$s

asked Mar 2, 2015 at 15:58

4 votes

1 answer

214 views

Definition of the higher dimensional mapping tori

asked Jul 10, 2013 at 13:55

4 votes

0 answers

368 views

Intuition behind a proof showing a square is homeomorphic to a quotient of an interval

asked Feb 9, 2014 at 16:33

3 votes

1 answer

429 views

Repetitive tiling implies finite local complexity

asked May 2, 2013 at 15:19

3 votes

1 answer

227 views

Sufficient condition for a direct limit of abelian groups to be infinitely generated

asked May 10, 2013 at 14:45

3 votes

1 answer

754 views

How to test if a primitive matrix has an eigenvalue of unit modulus

asked Sep 15, 2015 at 16:19

3 votes

1 answer

183 views

If direct limits of matrices are isomorphic, is the direct limit of the transpose matrices also isomorphic?

asked Jul 8, 2014 at 13:31

3 votes

1 answer

122 views

Must every infinite subshift contain a non-periodic point?

asked Nov 21, 2019 at 23:26

3 votes

1 answer

218 views

When is the space of connected components Hausdorff?

asked Jun 28, 2020 at 15:04

2 votes

1 answer

197 views

Is the inverse limit of simplicial maps between finite directed graphs also a graph?

asked Oct 16, 2014 at 19:27

2 votes

1 answer

75 views

Exchanging limits when functions may not converge uniformly

asked Feb 5, 2019 at 16:28

2 votes

2 answers

231 views

Hyperbolic quadrilaterals with two adjacent right angles

asked Apr 21, 2013 at 17:06

2 votes

4 answers

579 views

Method for finding eigenplanes of a linear transformation.

asked Feb 10, 2013 at 22:09

0 votes

1 answer

73 views

Labeling edges of a cube with + and - so each face has an odd number of +s.

asked Oct 6, 2013 at 23:05

Stack Exchange Network

27 Questions

Slice of pizza with no crust

Geometric way to view the truncated braid groups?

Homeomorphic to the disk implies existence of fixed point common to all isometries?

Examples of falsified (or currently open) longstanding conjectures leading to large bodies of incorrect results.

Does taking the direct limit of chain complexes commute with taking homology?

Applications of TQFTs beyond physics

Equivalences and isomorphisms of short exact sequences

Can the n-string sphere braid group embed in to the (n+1)-string sphere braid group?

Properties of the Category of topological spaces with $n$ basepoints.

Showing that the loopspace $\Omega S^{\infty}$ is homotopic to $S^{\infty}$.

Higher dimensional analogue of the correspondence between $2$d TQFTs and Frobenius algebras?

Cohomology of the pullback of a fiber bundle over the torus (generalised Eilenberg-Moore spectral sequence?)

Applying Khovanov homology to two different non-trivial diagrams of the unknot

Finite strings of integers from $\{1,1,2,2,\ldots,n,n\}$ such that there are $k$ elements between the two $k$s

Definition of the higher dimensional mapping tori

Intuition behind a proof showing a square is homeomorphic to a quotient of an interval

Repetitive tiling implies finite local complexity

Sufficient condition for a direct limit of abelian groups to be infinitely generated

How to test if a primitive matrix has an eigenvalue of unit modulus

If direct limits of matrices are isomorphic, is the direct limit of the transpose matrices also isomorphic?

Must every infinite subshift contain a non-periodic point?

When is the space of connected components Hausdorff?

Is the inverse limit of simplicial maps between finite directed graphs also a graph?

Exchanging limits when functions may not converge uniformly

Hyperbolic quadrilaterals with two adjacent right angles

Method for finding eigenplanes of a linear transformation.

Labeling edges of a cube with + and - so each face has an odd number of +s.