User Dan Rust

60 votes

Accepted

An intuitive idea about fundamental group of $\mathbb{RP}^2$

answered May 6, 2013 at 17:44

47 votes

Does $G\cong G/H$ imply that $H$ is trivial?

answered Sep 11, 2013 at 21:00

46 votes

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Unit sphere in $\mathbb{R}^\infty$ is contractible?

answered Jan 19, 2013 at 21:19

45 votes

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What is the mathematical significance of Penrose tiles?

answered May 6, 2014 at 20:27

42 votes

What are the most overpowered theorems in mathematics?

answered Nov 7, 2013 at 13:51

38 votes

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Example of a non-hausdorff space

answered Dec 17, 2013 at 16:08

24 votes

Simply connected manifolds are orientable

answered May 8, 2014 at 14:53

23 votes

Are these 2 graphs isomorphic?

answered May 16, 2013 at 12:35

22 votes

Are there any open mathematical puzzles?

answered Oct 21, 2013 at 1:14

22 votes

Proving that $\mathbb{F}^\infty$ is infinite-dimensional.

answered Sep 5, 2013 at 10:19

22 votes

Visually deceptive "proofs" which are mathematically wrong

answered Apr 15, 2014 at 23:03

20 votes

What is the oldest open problem in geometry?

answered Aug 12, 2014 at 20:35

20 votes

List of interesting math podcasts?

answered Mar 12, 2013 at 20:58

17 votes

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Topological Meaning of semi-direct product

answered Jan 13, 2013 at 1:01

17 votes

What is $\pi_{31}(S^2)$?

answered May 15, 2013 at 11:27

16 votes

Area of intersection between two circles

answered May 26, 2013 at 13:52

15 votes

Why should Rubik's cube get attention from mathematicians?

answered Feb 24, 2013 at 17:15

15 votes

Homology group of Real projective plane

answered Apr 25, 2014 at 14:11

15 votes

Accepted

Does every irrational number contain arbitrarily long sequences of some digit?

answered Sep 5, 2015 at 0:00

13 votes

What does it mean when a bound is sharp?

answered Oct 26, 2016 at 10:05

12 votes

Higher Homotopy Group of a Product of Spaces

answered May 4, 2014 at 14:22

12 votes

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Pi might contain all finite sets, can it also contain infinite sets?

answered Sep 11, 2013 at 1:32

12 votes

Image of Intersection of sects not equal to intersection of images of sets

answered Sep 3, 2013 at 2:14

11 votes

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Fundamental group of the Klein bottle, using action of a group?

answered Feb 24, 2013 at 22:50

11 votes

$\mathbb{S}^2$ as a fibre bundle

answered Jul 3, 2013 at 11:41

10 votes

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What is the difference between differential topology and calculus on manifolds?

answered Aug 12, 2013 at 10:44

10 votes

How to show that a disjoint sum of metric spaces is metrizable?

answered Aug 20, 2013 at 13:45

10 votes

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Complement of a Topology

answered Jun 8, 2013 at 13:28

10 votes

$\mathbb{Z}$ and $\mathbb{Q}$ are not homeomorphic

answered Mar 31, 2013 at 14:22

10 votes

Accepted

Prove that some set is compact directly from definition

answered Sep 6, 2013 at 9:47

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764 Answers

An intuitive idea about fundamental group of $\mathbb{RP}^2$

Does $G\cong G/H$ imply that $H$ is trivial?

Unit sphere in $\mathbb{R}^\infty$ is contractible?

What is the mathematical significance of Penrose tiles?

What are the most overpowered theorems in mathematics?

Example of a non-hausdorff space

Simply connected manifolds are orientable

Are these 2 graphs isomorphic?

Are there any open mathematical puzzles?

Proving that $\mathbb{F}^\infty$ is infinite-dimensional.

Visually deceptive "proofs" which are mathematically wrong

What is the oldest open problem in geometry?

List of interesting math podcasts?

Topological Meaning of semi-direct product

What is $\pi_{31}(S^2)$?

Area of intersection between two circles

Why should Rubik's cube get attention from mathematicians?

Homology group of Real projective plane

Does every irrational number contain arbitrarily long sequences of some digit?

What does it mean when a bound is sharp?

Higher Homotopy Group of a Product of Spaces

Pi might contain all finite sets, can it also contain infinite sets?

Image of Intersection of sects not equal to intersection of images of sets

Fundamental group of the Klein bottle, using action of a group?

$\mathbb{S}^2$ as a fibre bundle

What is the difference between differential topology and calculus on manifolds?

How to show that a disjoint sum of metric spaces is metrizable?

Complement of a Topology

$\mathbb{Z}$ and $\mathbb{Q}$ are not homeomorphic

Prove that some set is compact directly from definition