User Stefan Kohl

73 votes

17 answers

9k views

Mathematical research published in the form of poems

asked Dec 29, 2013 at 15:51

52 votes

3 answers

5k views

Mathematical research in North Korea -- reference request

asked Jan 11, 2019 at 10:58

47 votes

1 answer

2k views

Transitivity on $\mathbb{N}_0$ -- a 42 problem

asked Jun 15, 2015 at 14:36

43 votes

1 answer

1k views

Can't one walk to infinity on the prime numbers with finitely many distinct affine steps?

asked May 13, 2018 at 15:45

39 votes

1 answer

2k views

Prime number races in 2 dimensions

asked Feb 1, 2013 at 21:50

33 votes

2 answers

1k views

Richness of the subgroup structure of p-groups

asked Feb 13, 2013 at 13:44

33 votes

3 answers

6k views

Are surjectivity and injectivity of polynomial functions from $\mathbb{Q}^n$ to $\mathbb{Q}$ algorithmically decidable?

asked Jul 29, 2013 at 17:33

33 votes

3 answers

3k views

Frequency of papers showing academic misconduct among the articles indexed by MathSciNet and Zentralblatt MATH

asked Apr 18, 2017 at 14:01

32 votes

3 answers

3k views

Order of products of elements in symmetric groups

asked Jan 4, 2013 at 22:10

30 votes

2 answers

2k views

Fractal-like structures arising from the action of a group on $\mathbb{Z}^2$

asked Mar 11, 2014 at 18:33

30 votes

5 answers

3k views

Parametric solutions of Pell's equation

asked Jan 26, 2015 at 12:52

29 votes

1 answer

2k views

Is pi = log_a(b) for some integers a, b > 1?

asked Jan 10, 2013 at 11:37

24 votes

1 answer

2k views

Algorithmic (un-)solvability of diophantine equations of given degree with given number of variables

asked May 24, 2015 at 16:17

23 votes

5 answers

1k views

Securing privacy of "who communicates with whom" under Orwell-like conditions

asked Oct 29, 2013 at 11:29

22 votes

4 answers

2k views

Freeness of a Z[x]-module

asked Jun 10, 2013 at 17:00

22 votes

1 answer

1k views

Numbers of distinct products obtained by permuting the factors

asked Mar 7, 2013 at 17:16

22 votes

3 answers

3k views

Is the sum of the reciprocals of the products of pairs of coprime positive integers and their sums equal to 2?

asked Nov 11, 2023 at 17:01

21 votes

3 answers

930 views

Primes occurring as orders of elements of a finitely presented group

asked Feb 8, 2013 at 11:56

21 votes

1 answer

564 views

Partitions of ${\rm Sym}(\mathbb{N})$ induced by convergent, but not absolutely convergent series

asked Oct 8, 2014 at 10:44

19 votes

1 answer

2k views

How many primes can there be in a short interval?

asked Apr 6, 2016 at 10:33

18 votes

2 answers

2k views

Existence of polynomials of degree $\geq 2$ which represent infinitely many prime numbers

asked Jun 6, 2015 at 20:30

18 votes

1 answer

664 views

How hard is it to find a prime number with given primitive roots?

asked Jul 31, 2022 at 20:14

17 votes

1 answer

1k views

A converse of the abc conjecture?

asked Feb 20, 2016 at 22:14

17 votes

0 answers

969 views

Groups generated by 3 involutions

asked Nov 15, 2012 at 22:14

16 votes

0 answers

784 views

How to explain the picturesque patterns in François Brunault's matrix?

asked Jun 14, 2013 at 11:13

16 votes

1 answer

916 views

Is it true that every f.g. infinite simple group has exponential growth?

asked Feb 18, 2013 at 17:03

16 votes

1 answer

912 views

An equality involving roots of unity which holds most of the times, but not always

asked Apr 4, 2016 at 15:54

16 votes

1 answer

1k views

Are the algebraic numbers dense everywhere on the boundary of the Mandelbrot set?

asked Oct 11, 2015 at 19:45

15 votes

1 answer

1k views

Free subgroups of $\mathrm{GL}(2,\mathbb{Z})$

asked Jan 25, 2013 at 19:51

14 votes

2 answers

878 views

Sets of evenly distributed points in the Euclidean plane

asked Aug 29, 2013 at 16:42

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79 Questions

Mathematical research published in the form of poems

Mathematical research in North Korea -- reference request

Transitivity on $\mathbb{N}_0$ -- a 42 problem

Can't one walk to infinity on the prime numbers with finitely many distinct affine steps?

Prime number races in 2 dimensions

Richness of the subgroup structure of p-groups

Are surjectivity and injectivity of polynomial functions from $\mathbb{Q}^n$ to $\mathbb{Q}$ algorithmically decidable?

Frequency of papers showing academic misconduct among the articles indexed by MathSciNet and Zentralblatt MATH

Order of products of elements in symmetric groups

Fractal-like structures arising from the action of a group on $\mathbb{Z}^2$

Parametric solutions of Pell's equation

Is pi = log_a(b) for some integers a, b > 1?

Algorithmic (un-)solvability of diophantine equations of given degree with given number of variables

Securing privacy of "who communicates with whom" under Orwell-like conditions

Freeness of a Z[x]-module

Numbers of distinct products obtained by permuting the factors

Is the sum of the reciprocals of the products of pairs of coprime positive integers and their sums equal to 2?

Primes occurring as orders of elements of a finitely presented group

Partitions of ${\rm Sym}(\mathbb{N})$ induced by convergent, but not absolutely convergent series

How many primes can there be in a short interval?

Existence of polynomials of degree $\geq 2$ which represent infinitely many prime numbers

How hard is it to find a prime number with given primitive roots?

A converse of the abc conjecture?

Groups generated by 3 involutions

How to explain the picturesque patterns in François Brunault's matrix?

Is it true that every f.g. infinite simple group has exponential growth?

An equality involving roots of unity which holds most of the times, but not always

Are the algebraic numbers dense everywhere on the boundary of the Mandelbrot set?

Free subgroups of $\mathrm{GL}(2,\mathbb{Z})$

Sets of evenly distributed points in the Euclidean plane