Question

Show that for every uncountable $A \subseteq \omega_1$, the set $\{\alpha \in Lim(\omega_1): A_\alpha \subseteq A\}$ is stationary in $\omega_1$

score 328 · Answer 1 · 2026-04-11 01:25:17

Show that for every uncountable $A \subseteq \omega_1$, the set $\{\alpha \in Lim(\omega_1): A_\alpha \subseteq A\}$ is stationary in $\omega_1$

score 72 · Answer 2 · 2026-04-14 22:11:30

72

Views

Ramsey cardinals lemma

Published on 14 Apr 2026 - 22:11

score 147 · Answer 3 · 2026-04-14 07:25:36

147

Views

Simple property of arrow notation

Published on 14 Apr 2026 - 7:25

score 209 · Answer 4 · 2026-04-09 17:31:22

209

Views

almost disjoint functions from $\aleph_{\omega+1}$ to $\aleph_\omega$

Published on 09 Apr 2026 - 17:31

score 293 · Answer 5 · 2026-04-15 19:57:30

293

Views

Building normal filters around a stationary set

Published on 15 Apr 2026 - 19:57

score 75 · Answer 6 · 2026-04-11 02:29:50

75

Views

How to show that every Suslin tree is Frechet-Urysohn

Published on 11 Apr 2026 - 2:29

score 138 · Answer 7 · 2026-03-25 16:14:04

138

Views

Can we construct from $[0,\omega_1)$ a space which is strictly-Frechet with no winning strategy in $G_{np}(q,E)$?

Published on 25 Mar 2026 - 16:14

score 121 · Answer 8 · 2026-04-17 02:10:35

121

Views

What can we say about the one point compactification of a Suslin tree?

Published on 17 Apr 2026 - 2:10

score 167 · Answer 9 · 2026-04-14 11:46:12

167

Views

A non-first-countable topological space in which ONE has a winning strategy in $G_{np}(q,E)$ .

Published on 14 Apr 2026 - 11:46

score 136 · Answer 10 · 2026-04-14 07:44:27

136

Views

The point-open game and $\omega$-covers

Published on 14 Apr 2026 - 7:44

score 84 · Answer 11 · 2026-03-25 16:13:39

84

Views

Does any $\omega$-cover in which $X \in L(\mathcal U)$ is also a $\gamma$-cover?

Published on 25 Mar 2026 - 16:13

score 409 · Answer 12 · 2026-04-13 17:46:11

409

Views

Hindman's theorem on coloring a set with $n$ colours

Published on 13 Apr 2026 - 17:46

score 224 · Answer 13 · 2026-04-15 14:12:29

224

Views

countably closed forcing cannot add a branch to a $\aleph_2$-tree if $\neg\mathsf{CH}$

Published on 15 Apr 2026 - 14:12

score 149 · Answer 14 · 2026-04-14 13:49:28

149

Views

Is this an equivalent characterization of rapid filters?

Published on 14 Apr 2026 - 13:49

score 322 · Answer 15 · 2026-04-09 21:18:46

322

Views

Martin's Axiom and products of c.c.c. spaces

Published on 09 Apr 2026 - 21:18

List Question

Show that for every uncountable $A \subseteq \omega_1$, the set $\{\alpha \in Lim(\omega_1): A_\alpha \subseteq A\}$ is stationary in $\omega_1$

Ramsey cardinals lemma

Simple property of arrow notation

almost disjoint functions from $\aleph_{\omega+1}$ to $\aleph_\omega$

Building normal filters around a stationary set

How to show that every Suslin tree is Frechet-Urysohn

Can we construct from $[0,\omega_1)$ a space which is strictly-Frechet with no winning strategy in $G_{np}(q,E)$?

What can we say about the one point compactification of a Suslin tree?

A non-first-countable topological space in which ONE has a winning strategy in $G_{np}(q,E)$ .

The point-open game and $\omega$-covers

Does any $\omega$-cover in which $X \in L(\mathcal U)$ is also a $\gamma$-cover?

Hindman's theorem on coloring a set with $n$ colours

countably closed forcing cannot add a branch to a $\aleph_2$-tree if $\neg\mathsf{CH}$

Is this an equivalent characterization of rapid filters?

Martin's Axiom and products of c.c.c. spaces

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