User Dominic van der Zypen

6 votes

1 answer

189 views

$T_2$-spaces in which no two open sets are homeomorphic

asked Nov 1, 2018 at 6:56

6 votes

3 answers

468 views

Randomly picking $k$ members of $\{1,\ldots,n\}$

asked Oct 26, 2018 at 7:45

6 votes

1 answer

186 views

Chromatic number of a connected Hausdorff space

asked Jan 30, 2019 at 11:57

6 votes

3 answers

236 views

Refinement-minimal intersecting covers

asked Apr 16 at 16:40

6 votes

3 answers

801 views

Connected graphs isomorphic to their own contraction

asked Jan 14 at 16:40

6 votes

1 answer

221 views

Chromatic number of the infinite Erdős–Hajnal shift-graph

asked Mar 4 at 12:02

6 votes

1 answer

283 views

The Parity Principle and $\mathbf{C}_2$ (choice for $2$-sets)

asked Sep 13, 2023 at 10:27

6 votes

3 answers

315 views

Group such that factors in any product-decomposition are reducible

asked Nov 23, 2023 at 19:48

6 votes

1 answer

366 views

Large subgroups of Knuth's non-associative "group" on ${\cal P}(\mathbb{N})$

asked Dec 12, 2023 at 21:20

6 votes

2 answers

2k views

Expected maximum number of "prank cigarettes" in an average pack

asked Sep 18, 2022 at 19:52

6 votes

1 answer

229 views

Smallest ordinal $\mu$ not embeddable in ${\cal P}(\omega)$

asked Feb 8, 2023 at 21:03

6 votes

1 answer

356 views

Is every homogeneous poset a lattice?

asked May 18, 2023 at 8:47

6 votes

3 answers

260 views

Induced subgraphs of the almost-disjointness graph

asked May 14, 2021 at 13:07

6 votes

1 answer

111 views

Tameable hypergraphs

asked Mar 5, 2021 at 15:51

6 votes

1 answer

256 views

Maximal independent sets in MAD families

asked Mar 8, 2021 at 19:15

6 votes

2 answers

274 views

Expectation of period length of functions $f:\{1,\ldots,n\}\to \{1,\ldots,n\}$

asked Apr 4, 2021 at 23:11

6 votes

1 answer

1k views

Generalized Collatz sequences

asked Sep 27, 2020 at 13:45

6 votes

2 answers

118 views

Density of Ramsey subsets of $\omega$

asked Dec 23, 2020 at 13:09

6 votes

2 answers

304 views

Hamiltonian path in bike-lock graph with $1$ known digit

asked May 17, 2022 at 11:31

6 votes

1 answer

251 views

Gaps in cardinalities of MAD families

asked May 23, 2022 at 12:58

6 votes

2 answers

271 views

Infinite "almost rigid" homogeneous $T_2$-space

asked Mar 6, 2018 at 6:02

6 votes

6 answers

487 views

If $(X,\tau)$ has more than $1$ point and is $T_2$ and connected, do we have $|X| =|\tau|$?

asked May 21, 2018 at 12:12

6 votes

1 answer

497 views

Homeomorphic open sets and homogeneity

asked May 24, 2018 at 6:45

6 votes

1 answer

240 views

Countably infinite connected Hausdorff space with the fixed point property

asked Nov 19, 2017 at 19:43

6 votes

1 answer

241 views

Does $[0,1]\cap \mathbb{Q}$ have a connected $T_2$ quotient?

asked Nov 12, 2017 at 8:03

6 votes

1 answer

422 views

Clique and chromatic number of cycle graph of permutations

asked Oct 2, 2017 at 6:06

6 votes

0 answers

170 views

Katetov ordering on ideals on $\omega$

asked Oct 6, 2017 at 14:47

6 votes

1 answer

153 views

Topologies with no minimal $T_2$ topologies above them

asked Aug 9, 2017 at 9:03

6 votes

1 answer

211 views

Minimal subcoverings of a cover whose sets intersect in at most $1$ point

asked Aug 12, 2017 at 13:57

6 votes

0 answers

128 views

Edge-coloring number of a linear hypergraph

asked May 3, 2017 at 8:05

Stack Exchange Network

1,209 Questions

$T_2$-spaces in which no two open sets are homeomorphic

Randomly picking $k$ members of $\{1,\ldots,n\}$

Chromatic number of a connected Hausdorff space

Refinement-minimal intersecting covers

Connected graphs isomorphic to their own contraction

Chromatic number of the infinite Erdős–Hajnal shift-graph

The Parity Principle and $\mathbf{C}_2$ (choice for $2$-sets)

Group such that factors in any product-decomposition are reducible

Large subgroups of Knuth's non-associative "group" on ${\cal P}(\mathbb{N})$

Expected maximum number of "prank cigarettes" in an average pack

Smallest ordinal $\mu$ not embeddable in ${\cal P}(\omega)$

Is every homogeneous poset a lattice?

Induced subgraphs of the almost-disjointness graph

Tameable hypergraphs

Maximal independent sets in MAD families

Expectation of period length of functions $f:\{1,\ldots,n\}\to \{1,\ldots,n\}$

Generalized Collatz sequences

Density of Ramsey subsets of $\omega$

Hamiltonian path in bike-lock graph with $1$ known digit

Gaps in cardinalities of MAD families

Infinite "almost rigid" homogeneous $T_2$-space

If $(X,\tau)$ has more than $1$ point and is $T_2$ and connected, do we have $|X| =|\tau|$?

Homeomorphic open sets and homogeneity

Countably infinite connected Hausdorff space with the fixed point property

Does $[0,1]\cap \mathbb{Q}$ have a connected $T_2$ quotient?

Clique and chromatic number of cycle graph of permutations

Katetov ordering on ideals on $\omega$

Topologies with no minimal $T_2$ topologies above them

Minimal subcoverings of a cover whose sets intersect in at most $1$ point

Edge-coloring number of a linear hypergraph