diff --git a/properties/P000087.md b/properties/P000087.md index 218b0ac06..92302e328 100644 --- a/properties/P000087.md +++ b/properties/P000087.md @@ -17,3 +17,4 @@ Contrary to Munkres or Willard, we do not assume any separation axiom like {P3}, #### Meta-properties - This property is preserved by arbitrary products. +- This property is preserved by $\Sigma$-products. diff --git a/properties/P000186.md b/properties/P000186.md index 86224e785..40a361540 100644 --- a/properties/P000186.md +++ b/properties/P000186.md @@ -13,3 +13,4 @@ Homeomorphic to a subspace of a space that is {P87} and {P187}. - This property is hereditary. - This property is preserved by countable products. +- This property is preserved by $\Sigma$-products. diff --git a/spaces/S000035/properties/P000062.md b/spaces/S000035/properties/P000062.md new file mode 100644 index 000000000..6981cd361 --- /dev/null +++ b/spaces/S000035/properties/P000062.md @@ -0,0 +1,10 @@ +--- +space: S000035 +property: P000062 +value: false +--- + +Consider the open cover $\mathcal{O}=\{[0,\alpha)\mid \alpha \in X\}$. +Every countable subset of $\omega_1$ has an upper bound in $\omega_1$. +So if $\mathcal U$ is a countable subcollection of $\mathcal O$, there is some $\alpha\in\omega_1$ such that +$\bigcup\mathcal U\subseteq[0,\alpha]$, which is not dense in $X$. diff --git a/spaces/S000035/properties/P000082.md b/spaces/S000035/properties/P000082.md new file mode 100644 index 000000000..df6722ef8 --- /dev/null +++ b/spaces/S000035/properties/P000082.md @@ -0,0 +1,7 @@ +--- +space: S000035 +property: P000082 +value: true +--- + +For $\alpha \in X$ the open neighborhood $[0,\alpha + 1)\subseteq X$ is {P57} and {P190} and thus {P53} [(Explore)](https://topology.pi-base.org/spaces?q=Countable+%2B+Ordinal+space+%2B+%7EMetrizable).