User Sam Nead - MathOverflow

142 votes

Magic trick based on deep mathematics

answered Dec 27, 2009 at 23:23

52 votes

Examples of common false beliefs in mathematics

answered Apr 10, 2011 at 19:24

42 votes

What would you want to see at the Museum of Mathematics?

answered Dec 25, 2010 at 19:28

39 votes

Accepted

What part is left unsolved in the Unknotting problem? (after results of Bar-Natan, Khovanov, Kronheimer and Mrowka)

answered Feb 27, 2016 at 11:22

31 votes

Magic trick based on deep mathematics

answered Dec 25, 2009 at 23:19

29 votes

Drawing of the eight Thurston geometries?

answered Jul 7, 2010 at 10:42

21 votes

What group is $\langle a,b \,| \, a^2=b^2 \rangle$?

answered Dec 14, 2010 at 12:58

21 votes

Accepted

Collapsible group words

answered Jul 11, 2011 at 19:18

21 votes

Why is the fundamental group of a compact Riemann surface not free ?

answered Apr 6, 2012 at 22:24

21 votes

Accepted

Obtain any 3-manifold from repeating surgeries on knots in $S^3$

answered Mar 21, 2015 at 21:58

20 votes

Accepted

Teichmuller Theory introduction

answered Jan 2, 2010 at 20:31

19 votes

3-manifold with fundamental group $\mathbb Z$

answered Jan 25, 2021 at 8:47

19 votes

Is there a continuous partition of space into circles?

answered Oct 24, 2024 at 14:52

17 votes

How many digits of $\sqrt{2}$ are known to date?

answered May 4, 2023 at 21:36

17 votes

Rediscovery of lost mathematics

answered Apr 12, 2015 at 9:01

17 votes

Self-covering spaces

answered Mar 24, 2017 at 22:41

17 votes

Classification of homology 3-spheres?

answered Nov 10, 2009 at 2:24

16 votes

Problems known to be in both NP and coNP, but not known to be in P

answered Jul 14, 2010 at 10:49

16 votes

In knot theory: Benefits of working in $S^3$ instead of $\mathbb{R}^3$?

answered Apr 27, 2011 at 15:34

16 votes

How would a topologist explain "every Riemann surface of genus $g$ is hyperelliptic if and only if $g=2$"?

answered Aug 28, 2021 at 7:45

16 votes

Accepted

Fixed-point free diffeomorphisms of surfaces fixing no homology classes

answered Jun 30, 2022 at 21:49

16 votes

Examples of locally hyperbolic groups

answered Jul 3, 2022 at 22:13

16 votes

Topology of the space of embedded genus $g$ surfaces in $S^3$

answered Nov 16, 2022 at 22:28

15 votes

Accepted

Is there a contractible hyperbolic 3-orbifold of finite volume?

answered Nov 27, 2022 at 21:06

15 votes

Computational complexity theoretic incompleteness: is that a thing?

answered Jan 3, 2023 at 15:55

14 votes

Accepted

Definition of Thurston's skinning map

answered Feb 12, 2023 at 8:27

14 votes

Accepted

Is this a sleight of hand or a video edit?

answered Dec 28, 2009 at 13:52

14 votes

Books you would like to see translated into English

answered Mar 11, 2010 at 23:50

14 votes

Can you do math without knowing how to count?

answered Apr 17, 2021 at 14:22

13 votes

Accepted

How many knots are there with hyperbolic volume less than a given constant

answered Jan 18, 2015 at 17:28

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528 Answers

Magic trick based on deep mathematics

Examples of common false beliefs in mathematics

What would you want to see at the Museum of Mathematics?

What part is left unsolved in the Unknotting problem? (after results of Bar-Natan, Khovanov, Kronheimer and Mrowka)

Magic trick based on deep mathematics

Drawing of the eight Thurston geometries?

What group is $\langle a,b \,| \, a^2=b^2 \rangle$?

Collapsible group words

Why is the fundamental group of a compact Riemann surface not free ?

Obtain any 3-manifold from repeating surgeries on knots in $S^3$

Teichmuller Theory introduction

3-manifold with fundamental group $\mathbb Z$

Is there a continuous partition of space into circles?

How many digits of $\sqrt{2}$ are known to date?

Rediscovery of lost mathematics

Self-covering spaces

Classification of homology 3-spheres?

Problems known to be in both NP and coNP, but not known to be in P

In knot theory: Benefits of working in $S^3$ instead of $\mathbb{R}^3$?

How would a topologist explain "every Riemann surface of genus $g$ is hyperelliptic if and only if $g=2$"?

Fixed-point free diffeomorphisms of surfaces fixing no homology classes

Examples of locally hyperbolic groups

Topology of the space of embedded genus $g$ surfaces in $S^3$

Is there a contractible hyperbolic 3-orbifold of finite volume?

Computational complexity theoretic incompleteness: is that a thing?

Definition of Thurston's skinning map

Is this a sleight of hand or a video edit?

Books you would like to see translated into English

Can you do math without knowing how to count?

How many knots are there with hyperbolic volume less than a given constant