summaryrefslogtreecommitdiff
path: root/library/topology/topological-space.tex
diff options
context:
space:
mode:
Diffstat (limited to 'library/topology/topological-space.tex')
-rw-r--r--library/topology/topological-space.tex26
1 files changed, 7 insertions, 19 deletions
diff --git a/library/topology/topological-space.tex b/library/topology/topological-space.tex
index 7ff588d..c40aba4 100644
--- a/library/topology/topological-space.tex
+++ b/library/topology/topological-space.tex
@@ -239,18 +239,12 @@
Then $A \subseteq \unions{F}$.
\end{proposition}
\begin{proof}
- \begin{byCase}
- %\caseOf{$F$ is empty.}
- %For all $X$ we have $X \notin F$.
- %If $X \in F$ and $A \in X$ then $A \in F$.
- %Contradiction by assumption.
- %Omitted.
- \caseOf{$F$ is inhabited.}
- There exist $X \in F$ such that $X \subseteq \unions{F}$.
- $A \subseteq X \subseteq \unions{F}$.
- \end{byCase}
+ There exist $X \in F$ such that $X \subseteq \unions{F}$.
+ $A \subseteq X \subseteq \unions{F}$.
\end{proof}
+
+
\begin{proposition}\label{subseteq_inters_iff_to_left}
Let $A,F$ be sets.
Suppose $F$ is inhabited. % TODO:Remove!!
@@ -379,10 +373,6 @@
Then $a \notin \unions{F'}$.
Therefore $a \in \carrier[X] \setminus (\unions{F'})$.
\end{subproof}
-
-
-
-
We show that for all $a \in \carrier[X] \setminus (\unions{F'})$ we have $a \in \inters{F}$.
\begin{subproof}
\begin{byCase}
@@ -426,17 +416,15 @@
\end{byCase}
\end{proof}
-\begin{definition}\label{set_of_closeds}
- $\closeds[X] = \{ Y \in \pow{\carrier[X]} \mid \text{$Y$ is closed in $X$}\}$.
-\end{definition}
+
\begin{proposition}\label{closure_is_minimal_closed_set}
Let $X$ be a topological space.
Suppose $A \subseteq \carrier[X]$.
- For all $Y \in \closeds[X]$ such that $A \subseteq Y$ we have $\closure{A}{X} \subseteq Y$.
+ For all $Y \in \closeds{X}$ such that $A \subseteq Y$ we have $\closure{A}{X} \subseteq Y$.
\end{proposition}
\begin{proof}
- Follows by \cref{closure,set_of_closeds,inters_subseteq_elem,closures}.
+ Follows by \cref{closure,closeds,inters_subseteq_elem,closures}.
\end{proof}
\begin{proposition}\label{complement_interior_eq_closure_complement}