diff --git a/properties/P000026.md b/properties/P000026.md index f23fb7fa7a..de834aa8a5 100644 --- a/properties/P000026.md +++ b/properties/P000026.md @@ -11,3 +11,8 @@ refs: A space with a countable dense subset. Defined on page 7 of {{zb:0386.54001}}. + +---- +#### Meta-properties + +- $X$ satisfies this property iff its Kolmogorov quotient $\text{Kol}(X)$ does. diff --git a/properties/P000051.md b/properties/P000051.md index 53cd08d15e..d61edd2c07 100644 --- a/properties/P000051.md +++ b/properties/P000051.md @@ -25,3 +25,6 @@ Defined as "dispersed" in e.g. {{zb:0164.53101}}. #### Meta-properties - This property is hereditary. +- This property is preserved by finer topologies. +- This property is preserved by arbitrary disjoint unions. +- This property is preserved by finite products. diff --git a/spaces/S000207/properties/P000051.md b/spaces/S000207/properties/P000051.md new file mode 100644 index 0000000000..ec18b39460 --- /dev/null +++ b/spaces/S000207/properties/P000051.md @@ -0,0 +1,7 @@ +--- +space: S000207 +property: P000051 +value: true +--- + +$X$ is finer than $\omega_1 \times (\omega_1 + 1)$ with the product topology, {S35|P51} and {S36|P51}. diff --git a/spaces/S000207/properties/P000062.md b/spaces/S000207/properties/P000062.md new file mode 100644 index 0000000000..edf7b15013 --- /dev/null +++ b/spaces/S000207/properties/P000062.md @@ -0,0 +1,7 @@ +--- +space: S000207 +property: P000062 +value: false +--- + +Consider the open cover $\{[0,\alpha]\times (\omega_1 + 1) \mid \alpha \in \omega_1\}$. This has no dense countable subcollection by a similar argument given as in {S35|P62}. diff --git a/spaces/S000207/properties/P000081.md b/spaces/S000207/properties/P000081.md new file mode 100644 index 0000000000..2fb60c4fe7 --- /dev/null +++ b/spaces/S000207/properties/P000081.md @@ -0,0 +1,7 @@ +--- +space: S000207 +property: P000081 +value: false +--- + +The subspace $\{0\}\times (\omega_1 + 1)\subseteq X$ is homeomorphic to {S155} and {S155|P81}. diff --git a/spaces/S000207/properties/P000114.md b/spaces/S000207/properties/P000114.md new file mode 100644 index 0000000000..cbe8f47777 --- /dev/null +++ b/spaces/S000207/properties/P000114.md @@ -0,0 +1,7 @@ +--- +space: S000207 +property: P000114 +value: true +--- + +Since $|\omega_1|=|\omega_1 + 1| = \aleph_1$.