From 4c99660d40d66d6f48b5b0796b75a20c3e2d51ae Mon Sep 17 00:00:00 2001 From: Patrick Rabau Date: Sat, 28 Sep 2024 12:37:03 -0400 Subject: [PATCH] More aleph_0 spaces --- spaces/S000131/properties/P000183.md | 14 ++++++++++++++ spaces/S000139/properties/P000183.md | 10 ++++++++++ spaces/S000156/README.md | 2 +- spaces/S000156/properties/P000183.md | 10 ++++++++++ 4 files changed, 35 insertions(+), 1 deletion(-) create mode 100644 spaces/S000131/properties/P000183.md create mode 100644 spaces/S000139/properties/P000183.md create mode 100644 spaces/S000156/properties/P000183.md diff --git a/spaces/S000131/properties/P000183.md b/spaces/S000131/properties/P000183.md new file mode 100644 index 000000000..7e59be3ad --- /dev/null +++ b/spaces/S000131/properties/P000183.md @@ -0,0 +1,14 @@ +--- +space: S000131 +property: P000183 +value: true +refs: + - mathse: 4844426 + name: Answer to "Can a Fréchet-Urysohn hemicompact Hausdorff space fail to be locally compact?" +--- + +Each spine $C_m=(\{m\}\times\omega)\cup\{\infty\}$ is a closed subspace of $X$ homeomorphic to a convergent sequence ({S20}); +and {S20|P183}. +And every compact subset of $X$ is contained in the union of a finite number of these spines. + +Therefore, taking a countable $k$-network from each of the (countably many) spines and forming their union gives a countable $k$-network for $X.$ diff --git a/spaces/S000139/properties/P000183.md b/spaces/S000139/properties/P000183.md new file mode 100644 index 000000000..b97344c4a --- /dev/null +++ b/spaces/S000139/properties/P000183.md @@ -0,0 +1,10 @@ +--- +space: S000139 +property: P000183 +value: true +--- + +Each of the circles (corresponding to an interval $[n,n+1]$, $n\in\mathbb Z$, with the endpoints identified) is a closed subspace of $X$ and {S170|P183}. +And every compact subset of $X$ is contained in the union of a finite number of these circles. + +Therefore, taking a countable $k$-network from each of the (countably many) circles and forming their union gives a countable $k$-network for $X.$ diff --git a/spaces/S000156/README.md b/spaces/S000156/README.md index 82e41b3ce..92d1f20fd 100644 --- a/spaces/S000156/README.md +++ b/spaces/S000156/README.md @@ -2,7 +2,7 @@ uid: S000156 name: Arens space aliases: -- S_2 +- $S_2$ refs: - mr: 37500 name: Note on convergence in topology (Arens) diff --git a/spaces/S000156/properties/P000183.md b/spaces/S000156/properties/P000183.md new file mode 100644 index 000000000..cc8826c16 --- /dev/null +++ b/spaces/S000156/properties/P000183.md @@ -0,0 +1,10 @@ +--- +space: S000156 +property: P000183 +value: true +refs: + - mathse: 4673444 + name: Answer to "Is the Arens space hemicompact but not locally compact?" +--- + +See the last part of {{mathse:4673444}}.