User Roland Bacher

24 votes

Conceptual reason why the sign of a permutation is well-defined?

answered Mar 9, 2022 at 9:47

21 votes

Invertible matrices of natural numbers are permutations... why?

answered Apr 18, 2011 at 14:47

20 votes

How to write mathematics without typing?

answered Feb 10 at 9:25

18 votes

Accepted

Can the circle be characterized by the following property?

answered Apr 20, 2010 at 17:16

16 votes

How can you find an integer coefficient polynomial knowing its values only at a few points (but requiring the coefficients be small)?

answered Sep 25, 2021 at 10:45

15 votes

4900, a particularly square number

answered May 31, 2010 at 11:05

14 votes

Thinking and Explaining

answered Sep 16, 2010 at 6:44

13 votes

Representation theory of $S_n$

answered Apr 19, 2011 at 6:47

13 votes

Determinant of sum of positive definite matrices

answered May 20, 2011 at 6:53

13 votes

Math puzzles for dinner

answered Jun 24, 2010 at 9:08

13 votes

Experimental mathematics leading to major advances

answered Apr 30, 2010 at 7:35

13 votes

What is the simplest proof that the density of coprime pairs does not go to zero?

answered Sep 13, 2023 at 12:27

12 votes

How small can a sum of a few roots of unity be?

answered Nov 15, 2010 at 11:52

11 votes

Density of a set of natural numbers whose differences are not bounded.

answered May 27, 2011 at 16:14

11 votes

Accepted

Probability of generating the symmetric group

answered Aug 5, 2010 at 8:37

11 votes

The sparsest planar net that captures every unit segment

answered Nov 16, 2012 at 15:52

10 votes

Which theorems have Pythagoras' Theorem as a special case?

answered May 6, 2022 at 9:30

10 votes

Examples of theorems misapplied to non-mathematical contexts

answered Jun 1, 2011 at 6:20

9 votes

Classification of finite groups of isometries

answered Aug 30, 2010 at 12:39

9 votes

Finite subgroups of ${\rm SL}_2(\mathbb{Z})$ (reference request)

answered Jun 7, 2010 at 7:43

9 votes

Accepted

Can select many disjoint pairs with prescribed differences from Z_n?

answered May 10, 2010 at 14:50

9 votes

Is amateur research in mathematics viable?

answered May 11, 2022 at 8:41

9 votes

Examples of bad notation and its consequences

answered Apr 20, 2023 at 6:21

9 votes

Accepted

The Problem about 2-coloring finite plane

answered Feb 21, 2012 at 9:11

9 votes

Open problems in Euclidean geometry?

answered Apr 15, 2015 at 8:30

9 votes

Prominent non-mathematical work of mathematicians

answered Aug 16, 2021 at 15:17

8 votes

Graphs from the point of view of Riemann surfaces

answered Nov 22, 2021 at 11:24

8 votes

Published results: when to take them for granted?

answered May 7, 2010 at 8:44

8 votes

how can I minimise (n * y) (mod x) for known x and y, and for a given range of n?

answered Jun 14, 2010 at 14:55

8 votes

Examples where physical heuristics led to incorrect answers?

answered Jul 1, 2010 at 13:18

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150 Answers

Conceptual reason why the sign of a permutation is well-defined?

Invertible matrices of natural numbers are permutations... why?

How to write mathematics without typing?

Can the circle be characterized by the following property?

How can you find an integer coefficient polynomial knowing its values only at a few points (but requiring the coefficients be small)?

4900, a particularly square number

Thinking and Explaining

Representation theory of $S_n$

Determinant of sum of positive definite matrices

Math puzzles for dinner

Experimental mathematics leading to major advances

What is the simplest proof that the density of coprime pairs does not go to zero?

How small can a sum of a few roots of unity be?

Density of a set of natural numbers whose differences are not bounded.

Probability of generating the symmetric group

The sparsest planar net that captures every unit segment

Which theorems have Pythagoras' Theorem as a special case?

Examples of theorems misapplied to non-mathematical contexts

Classification of finite groups of isometries

Finite subgroups of ${\rm SL}_2(\mathbb{Z})$ (reference request)

Can select many disjoint pairs with prescribed differences from Z_n?

Is amateur research in mathematics viable?

Examples of bad notation and its consequences

The Problem about 2-coloring finite plane

Open problems in Euclidean geometry?

Prominent non-mathematical work of mathematicians

Graphs from the point of view of Riemann surfaces

Published results: when to take them for granted?

how can I minimise (n * y) (mod x) for known x and y, and for a given range of n?

Examples where physical heuristics led to incorrect answers?