summaryrefslogtreecommitdiff
path: root/library/topology
diff options
context:
space:
mode:
Diffstat (limited to 'library/topology')
-rw-r--r--library/topology/separation.tex14
1 files changed, 9 insertions, 5 deletions
diff --git a/library/topology/separation.tex b/library/topology/separation.tex
index f055495..530a51f 100644
--- a/library/topology/separation.tex
+++ b/library/topology/separation.tex
@@ -99,10 +99,6 @@
For all $y \in \unions{V}$ we have $y \in \carrier[X] \setminus \{x\}$.
Follows by set extensionality.
\end{subproof}
-
-
-
-
% Let $U_{y} \in \opens[X]$ such that $x \neq y \in X$. Error: unexpected '{' expecting digit
%For all $y$ there exists $U$ such that $x \neq y$ and $y \in U$ and $U \in \opens[X]$.
@@ -149,5 +145,13 @@
Then $X$ is a \teeone-space.
\end{proposition}
\begin{proof}
- Omitted. % TODO
+ We show that for all $x,y\in\carrier[X]$ such that $x\neq y$
+ there exist $U, V\in\opens[X]$ such that
+ $U\ni x\notin V$ and $V\ni y\notin U$.
+ \begin{subproof}
+ $X$ is hausdorff.
+ For all $x,y\in\carrier[X]$ such that $x\neq y$
+ there exist $U, V\in\opens[X]$ such that
+ $x\in U$ and $y\in V$ and $U$ is disjoint from $V$.
+ \end{subproof}
\end{proof}