User Roland Bacher

2 votes

Does $\mathbb Z^n$ contain $A_n$?

answered Feb 12 at 21:50

20 votes

How to write mathematics without typing?

answered Feb 10 at 9:25

5 votes

Reference request for a proof of the two-square Theorem

answered Nov 10, 2023 at 21:58

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

1 vote

Golden ratio base

answered Aug 1, 2023 at 12:27

6 votes

How many players are needed so that two evenly matched teams can be picked?

answered Jun 5, 2023 at 20:35

9 votes

Examples of bad notation and its consequences

answered Apr 20, 2023 at 6:21

1 vote

How many ways are there to pick $n$ points on the finite affine plane $(\Bbb F_q)^2$ such that no three are collinear?

answered Jan 13, 2023 at 19:06

0 votes

Minimum diameter of set inscribed in a unit sphere

answered Jan 10, 2023 at 17:12

2 votes

What's a nice argument that shows the volume of the unit ball in $\mathbb R^n$ approaches 0?

answered Dec 21, 2022 at 12:29

0 votes

In "splendid isolation"

answered Nov 9, 2022 at 8:20

0 votes

Nonplanar equilateral lattice "pentagons"

answered Oct 2, 2022 at 10:14

5 votes

Subgroup of a group with length 3 relators

answered Sep 17, 2022 at 7:16

1 vote

Are simplicial polytopes a dense set?

answered Sep 15, 2022 at 9:32

2 votes

Counterexamples in algebra?

answered Aug 12, 2022 at 16:32

1 vote

Mathematicians with both “very abstract” and “very applied” achievements

answered Aug 5, 2022 at 9:05

4 votes

Number of finite index subgroups in a free abelian group

answered Aug 4, 2022 at 12:52

1 vote

Accepted

"Lamp-switch set-up number" of $n$

answered May 15, 2022 at 12:36

10 votes

Is amateur research in mathematics viable?

answered May 11, 2022 at 8:41

5 votes

Resources where I can find open problems in number theory along with their level of difficulty

answered May 9, 2022 at 15:53

10 votes

Which theorems have Pythagoras' Theorem as a special case?

answered May 6, 2022 at 9:30

7 votes

Techniques for debugging proofs

answered May 4, 2022 at 16:01

24 votes

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

answered Mar 9, 2022 at 9:47

1 vote

Area-differences for lattice triangles in a checkerboard

answered Mar 7, 2022 at 16:18

6 votes

Modern results that are widely known, yet which at the time were ignored, not accepted or criticized

answered Feb 7, 2022 at 8:45

0 votes

Maximal packings of the integers

answered Jan 4, 2022 at 15:07

5 votes

Closed formula for $(-1)$-Baxter sequences

answered Dec 23, 2021 at 13:01

4 votes

Accepted

Find the order of a class of finite matrices over finite fields

answered Dec 10, 2021 at 10:40

1 vote

Accepted

Construct a rooted plane tree with nodes labelled

answered Dec 9, 2021 at 16:45

8 votes

Graphs from the point of view of Riemann surfaces

answered Nov 22, 2021 at 11:24

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149 Answers

Does $\mathbb Z^n$ contain $A_n$?

How to write mathematics without typing?

Reference request for a proof of the two-square Theorem

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

Golden ratio base

How many players are needed so that two evenly matched teams can be picked?

Examples of bad notation and its consequences

How many ways are there to pick $n$ points on the finite affine plane $(\Bbb F_q)^2$ such that no three are collinear?

Minimum diameter of set inscribed in a unit sphere

What's a nice argument that shows the volume of the unit ball in $\mathbb R^n$ approaches 0?

In "splendid isolation"

Nonplanar equilateral lattice "pentagons"

Subgroup of a group with length 3 relators

Are simplicial polytopes a dense set?

Counterexamples in algebra?

Mathematicians with both “very abstract” and “very applied” achievements

Number of finite index subgroups in a free abelian group

"Lamp-switch set-up number" of $n$

Is amateur research in mathematics viable?

Resources where I can find open problems in number theory along with their level of difficulty

Which theorems have Pythagoras' Theorem as a special case?

Techniques for debugging proofs

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

Area-differences for lattice triangles in a checkerboard

Modern results that are widely known, yet which at the time were ignored, not accepted or criticized

Maximal packings of the integers

Closed formula for $(-1)$-Baxter sequences

Find the order of a class of finite matrices over finite fields

Construct a rooted plane tree with nodes labelled

Graphs from the point of view of Riemann surfaces