User Dominic van der Zypen

3 votes

2 answers

182 views

Property ${\bf B}$ for families of large sets with small intersection

asked Nov 19, 2022 at 15:51

3 votes

1 answer

137 views

Representing graphs by $\text{Hom}$-graphs

asked Dec 9, 2022 at 14:19

3 votes

0 answers

108 views

Hamiltonian path in $\{0,1\}^n$ with rotations and bit-flip in position 0

asked Sep 20, 2022 at 10:40

3 votes

1 answer

100 views

Property $\mathbf{B}$ for maximal linear set systems on $\omega$ with finite members

asked Oct 20, 2022 at 9:36

3 votes

1 answer

153 views

Cycling through a general combinatorial design on $\omega$

asked Oct 27, 2022 at 19:00

3 votes

1 answer

135 views

$3\times 3$ magic squares consisting of entries of a dense set $D\subseteq \mathbb{N}$

asked Aug 2, 2022 at 8:28

3 votes

1 answer

126 views

The sequence of the power chromatic numbers $(\chi(G^n))_{n\in\mathbb{N}}$

asked Aug 14, 2023 at 14:04

3 votes

1 answer

228 views

Are "ultra-regular" bipartite graphs complete?

asked Oct 20, 2023 at 9:02

3 votes

2 answers

622 views

Non-simple groups $G$ with only non-trivial quotient isomorphic to $G$

asked Nov 28, 2023 at 8:45

3 votes

2 answers

347 views

Are there $2^{\aleph_0}$ pairwise non-isomorphic countable groups containing every finite group?

asked Nov 16, 2023 at 12:46

3 votes

1 answer

271 views

A possible ${\sf (ZF)}$-theorem in the spirit of the $3$-set-lemma

asked Feb 22 at 14:52

3 votes

1 answer

132 views

Chromatic number of triangle-free graph $[[n]]^2$ with edges of form $a<b, b<c$

asked Mar 2 at 22:09

3 votes

2 answers

121 views

Set sizes in linear set systems on $\mathbb{N}$ containing some disjoint sets

asked Feb 1 at 9:58

3 votes

1 answer

104 views

Cardinality of splitting families

asked May 4 at 18:38

3 votes

1 answer

120 views

Non-isomorphic $T_0$-spaces with order-isomorphic topologies

asked May 5 at 21:00

3 votes

1 answer

400 views

Projective graphs

asked Feb 1, 2019 at 10:39

3 votes

0 answers

83 views

Decreasing the directed chromatic number of a digraph by adding an edge

asked Feb 8, 2019 at 8:58

3 votes

1 answer

274 views

Does every directed graph have a directed coloring with $4$ colors?

asked Feb 10, 2019 at 12:42

3 votes

1 answer

298 views

Extending a continuous self-map of an open subset to the whole space

asked Feb 25, 2019 at 15:08

3 votes

2 answers

170 views

Rigid space, but with homeomorphic neighborhoods

asked Feb 13, 2019 at 11:53

3 votes

2 answers

236 views

Expected value of length of interval game

asked Feb 22, 2019 at 6:39

3 votes

1 answer

239 views

Computabillity of packing of spheres with different radii

asked Apr 28, 2019 at 6:29

3 votes

1 answer

82 views

Stretching map of $n$ points from $\{0,1\}^n$ to $\{0,1\}^{n+1}$ with respect to their Hamming distance

asked Dec 20, 2018 at 15:12

3 votes

2 answers

570 views

Connected topological space $X$ such that $\emptyset, X$ are the only open connected subsets

asked Dec 22, 2018 at 14:58

3 votes

1 answer

126 views

A set coverage problem

asked Dec 16, 2018 at 8:51

3 votes

1 answer

99 views

Maximal matchings in connected graphs

asked Sep 16, 2018 at 9:25

3 votes

1 answer

71 views

$|V|$ and $|E|$ in hypergraphs with a separation property

asked Oct 9, 2018 at 18:51

3 votes

1 answer

2k views

Two reasons why the Collatz conjecture could fail

asked Oct 20, 2018 at 13:48

3 votes

2 answers

194 views

Is every uncountable, homogeneous connected $T_2$-space isomorphic to a subspace of $\mathbb{R}^\omega$?

asked Nov 5, 2018 at 15:10

3 votes

1 answer

111 views

Function $f:\kappa\to\alpha$ with small fibers where $\alpha\in\kappa$

asked Nov 10, 2018 at 9:17

Stack Exchange Network

1,209 Questions

Property ${\bf B}$ for families of large sets with small intersection

Representing graphs by $\text{Hom}$-graphs

Hamiltonian path in $\{0,1\}^n$ with rotations and bit-flip in position 0

Property $\mathbf{B}$ for maximal linear set systems on $\omega$ with finite members

Cycling through a general combinatorial design on $\omega$

$3\times 3$ magic squares consisting of entries of a dense set $D\subseteq \mathbb{N}$

The sequence of the power chromatic numbers $(\chi(G^n))_{n\in\mathbb{N}}$

Are "ultra-regular" bipartite graphs complete?

Non-simple groups $G$ with only non-trivial quotient isomorphic to $G$

Are there $2^{\aleph_0}$ pairwise non-isomorphic countable groups containing every finite group?

A possible ${\sf (ZF)}$-theorem in the spirit of the $3$-set-lemma

Chromatic number of triangle-free graph $[[n]]^2$ with edges of form $a<b, b<c$

Set sizes in linear set systems on $\mathbb{N}$ containing some disjoint sets

Cardinality of splitting families

Non-isomorphic $T_0$-spaces with order-isomorphic topologies

Projective graphs

Decreasing the directed chromatic number of a digraph by adding an edge

Does every directed graph have a directed coloring with $4$ colors?

Extending a continuous self-map of an open subset to the whole space

Rigid space, but with homeomorphic neighborhoods

Expected value of length of interval game

Computabillity of packing of spheres with different radii

Stretching map of $n$ points from $\{0,1\}^n$ to $\{0,1\}^{n+1}$ with respect to their Hamming distance

Connected topological space $X$ such that $\emptyset, X$ are the only open connected subsets

A set coverage problem

Maximal matchings in connected graphs

$|V|$ and $|E|$ in hypergraphs with a separation property

Two reasons why the Collatz conjecture could fail

Is every uncountable, homogeneous connected $T_2$-space isomorphic to a subspace of $\mathbb{R}^\omega$?

Function $f:\kappa\to\alpha$ with small fibers where $\alpha\in\kappa$