From 463478fe2d7da7266a15a87ce5db568361ad0978 Mon Sep 17 00:00:00 2001 From: Patrick Rabau <70125716+prabau@users.noreply.github.com> Date: Thu, 13 Aug 2026 02:12:04 -0400 Subject: [PATCH 1/2] More traits for S125 Knaster-Kuratowski fan --- spaces/S000125/README.md | 9 ++++++--- spaces/S000125/properties/P000022.md | 11 ----------- spaces/S000125/properties/P000023.md | 11 ----------- spaces/S000125/properties/P000041.md | 7 ++----- spaces/S000125/properties/P000055.md | 9 +++++++++ 5 files changed, 17 insertions(+), 30 deletions(-) delete mode 100644 spaces/S000125/properties/P000022.md delete mode 100644 spaces/S000125/properties/P000023.md create mode 100644 spaces/S000125/properties/P000055.md diff --git a/spaces/S000125/README.md b/spaces/S000125/README.md index 50a52980d6..582d298313 100644 --- a/spaces/S000125/README.md +++ b/spaces/S000125/README.md @@ -10,11 +10,14 @@ refs: - wikipedia: Knaster-Kuratowski_fan name: Knaster-Kuratowski fan --- -For any $a \in [0,1]$, let $L(a)$ be the line segment from $(a,0)$ to $p = (\frac{1}{2}, \frac{1}{2})$. Let $\mathcal{C}$ be the middle-thirds Cantor set in the unit interval, $\mathcal{E}$ the endpoints of the removed intervals and $\mathcal{F} = \mathcal{C} \setminus \mathcal{E}$. Define $A = \{(x,y) \in L(c)\ |\ c \in \mathcal{E}, y \in \mathbb{Q}\}$ and $B = \{(x,y) \in L(c)\ |\ c \in \mathcal{F}, y \not\in \mathbb{Q}\}$. This space is $X = A \cup B \subset \mathbb{R}^2$ with the subspace topology. + +$X$ is a subspace of {S176} defined as follows. +For any $a \in [0,1]$, let $L(a)$ be the closed line segment from $(a,0)$ to $p = (\frac{1}{2}, \frac{1}{2})$. +Let $C$ be the middle-thirds Cantor set in the unit interval, $E$ the set of endpoints of the removed intervals and $F = C\setminus E$. +Define $A = \{(x,y) \in L(c):c \in E, y \in \mathbb Q\}$ and $B = \{(x,y) \in L(c):c \in F, y \not\in \mathbb Q\}$. +Then take $X = A \cup B\subseteq\mathbb R^2$ with the subspace topology. The subspace $X\setminus\{p\}$ obtained by removing the apex point is {S126}. Defined as counterexample #128 ("Cantor's Leaky Tent") in {{zb:0386.54001}}. - - diff --git a/spaces/S000125/properties/P000022.md b/spaces/S000125/properties/P000022.md deleted file mode 100644 index ebb2ee4948..0000000000 --- a/spaces/S000125/properties/P000022.md +++ /dev/null @@ -1,11 +0,0 @@ ---- -space: S000125 -property: P000022 -value: false -refs: -- zb: "0386.54001" - name: Counterexamples in Topology ---- - -Asserted in the General Reference Chart for space #128 in -{{zb:0386.54001}}. diff --git a/spaces/S000125/properties/P000023.md b/spaces/S000125/properties/P000023.md deleted file mode 100644 index e74a0a564b..0000000000 --- a/spaces/S000125/properties/P000023.md +++ /dev/null @@ -1,11 +0,0 @@ ---- -space: S000125 -property: P000023 -value: false -refs: -- zb: "0386.54001" - name: Counterexamples in Topology ---- - -Asserted in the General Reference Chart for space #128 in -{{zb:0386.54001}}. diff --git a/spaces/S000125/properties/P000041.md b/spaces/S000125/properties/P000041.md index 7818e1d031..6125857d9b 100644 --- a/spaces/S000125/properties/P000041.md +++ b/spaces/S000125/properties/P000041.md @@ -2,10 +2,7 @@ space: S000125 property: P000041 value: false -refs: -- zb: "0386.54001" - name: Counterexamples in Topology --- -Asserted in the General Reference Chart for space #128 in -{{zb:0386.54001}}. +{S126} is an open subset of $X$, +and {S126|P41}. diff --git a/spaces/S000125/properties/P000055.md b/spaces/S000125/properties/P000055.md new file mode 100644 index 0000000000..5206b2b684 --- /dev/null +++ b/spaces/S000125/properties/P000055.md @@ -0,0 +1,9 @@ +--- +space: S000125 +property: P000055 +value: false +--- + +For any $c\in E$ the closed set $L(c)\cap X\subseteq X$ is homeomorphic to $[0,1/2]\cap\mathbb Q$, +which in turn contains a closed set homeomorphic to {S27}. +And {S27|P55}. From a1924ae7f0df5a15fe8236e5f77c1f68977fe144 Mon Sep 17 00:00:00 2001 From: Patrick Rabau <70125716+prabau@users.noreply.github.com> Date: Wed, 19 Aug 2026 00:02:58 -0400 Subject: [PATCH 2/2] not Menger --- spaces/S000125/properties/P000055.md | 4 ++-- spaces/S000125/properties/P000066.md | 9 +++++++++ 2 files changed, 11 insertions(+), 2 deletions(-) create mode 100644 spaces/S000125/properties/P000066.md diff --git a/spaces/S000125/properties/P000055.md b/spaces/S000125/properties/P000055.md index 5206b2b684..97ff45df6c 100644 --- a/spaces/S000125/properties/P000055.md +++ b/spaces/S000125/properties/P000055.md @@ -4,6 +4,6 @@ property: P000055 value: false --- -For any $c\in E$ the closed set $L(c)\cap X\subseteq X$ is homeomorphic to $[0,1/2]\cap\mathbb Q$, -which in turn contains a closed set homeomorphic to {S27}. +Take some $c\in E$. +The closed set $L(c)\cap X\subseteq X$ contains a closed set homeomorphic to {S27}. And {S27|P55}. diff --git a/spaces/S000125/properties/P000066.md b/spaces/S000125/properties/P000066.md new file mode 100644 index 0000000000..c390447f19 --- /dev/null +++ b/spaces/S000125/properties/P000066.md @@ -0,0 +1,9 @@ +--- +space: S000125 +property: P000066 +value: false +--- + +Take some $c\in F$. +The closed set $L(c)\cap X\subseteq X$ contains a closed set homeomorphic to {S28}. +And {S28|P66}.