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-rw-r--r--library/topology/topological-space.tex25
1 files changed, 12 insertions, 13 deletions
diff --git a/library/topology/topological-space.tex b/library/topology/topological-space.tex
index 409e107..6ddf721 100644
--- a/library/topology/topological-space.tex
+++ b/library/topology/topological-space.tex
@@ -230,7 +230,7 @@
Follows by \cref{inters_singleton,closure}.
\end{proof}
-\begin{proposition}\label{subseteq_inters_iff_to_right}
+\begin{proposition}\label{subseteq_inters_iff_to_right}
Let $A,F$ be sets.
Suppose $A \subseteq \inters{F}$.
Then for all $X \in F$ we have $A \subseteq X$.
@@ -250,7 +250,7 @@
-\begin{proposition}\label{subseteq_inters_iff_to_left}
+\begin{proposition}\label{subseteq_inters_iff_to_left}
Let $A,F$ be sets.
Suppose $F$ is inhabited. % TODO:Remove!!
Suppose for all $X \in F$ we have $A \subseteq X$.
@@ -261,7 +261,7 @@
\caseOf{$A = \emptyset$.}Trivial.
\caseOf{$A \neq \emptyset$.}
$F$ is inhabited.
- It suffices to show that for all $a \in A$ we have $a \in \inters{F}$.
+ It suffices to show that for all $a \in A$ we have $a \in \inters{F}$.
Fix $a \in A$.
For all $X \in F$ we have $a \in X$.
$A \subseteq \unions{F}$.
@@ -269,7 +269,7 @@
\end{byCase}
\end{proof}
-\begin{proposition}\label{subseteq_inters_iff_new}
+\begin{proposition}\label{subseteq_inters_iff_new}
Suppose $F$ is inhabited.
$A \subseteq \inters{F}$ iff for all $X \in F$ we have $A \subseteq X$.
\end{proposition}
@@ -281,7 +281,7 @@
\end{proposition}
\begin{proof}
\begin{byCase}
- \caseOf{$A = \emptyset$.}
+ \caseOf{$A = \emptyset$.}
Trivial.
\caseOf{$A \neq \emptyset$.}
We show that $\carrier[X] \in \closures{A}{X}$.
@@ -289,7 +289,7 @@
$\carrier[X]$ is closed in $X$.
$\carrier[X] \in \pow{\carrier[X]}$.
\end{subproof}
- $\closures{A}{X}$ is inhabited.
+ $\closures{A}{X}$ is inhabited.
For all $A' \in \closures{A}{X}$ we have $A \subseteq A'$.
Therefore $A \subseteq \inters{\closures{A}{X}}$.
\end{byCase}
@@ -389,7 +389,7 @@
There exist $U' \in F'$ such that $U' = \carrier[X] \setminus U$.
Omitted.
\caseOf{$\inters{F} \neq \emptyset$.}
-
+
Fix $a \in \carrier[X] \setminus (\unions{F'})$.
$\inters{F}$ is inhabited.
$a \in \carrier[X]$.
@@ -414,7 +414,7 @@
\end{proposition}
\begin{proof}
\begin{byCase}
- \caseOf{$\closure{A}{X} = \emptyset$.}
+ \caseOf{$\closure{A}{X} = \emptyset$.}
Trivial.
\caseOf{$\closure{A}{X} \neq \emptyset$.}
$\closures{A}{X}$ is inhabited.
@@ -429,7 +429,7 @@
\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,closeds,inters_subseteq_elem,closures}.
@@ -449,21 +449,20 @@
\begin{proof}
We show that for all $x \in \carrier[X]\setminus\interior{A}{X}$ we have $x \in \closure{(\carrier[X]\setminus A)}{X}$.
\begin{subproof}
-
Fix $x \in \carrier[X]\setminus\interior{A}{X}$.
- Suppose not.
+ Suppose not.
$x \notin \closure{(\carrier[X]\setminus A)}{X}$.
$x \in \carrier[X]$.
$(\carrier[X] \setminus \closure{(\carrier[X]\setminus A)}{X}) \inter \closure{(\carrier[X]\setminus A)}{X} = \emptyset$.
$x \in A$.
$x \in A \inter (\carrier[X] \setminus \closure{(\carrier[X]\setminus A)}{X})$.
$\carrier[X] \setminus \closure{(\carrier[X]\setminus A)}{X} \in \opens[X]$.
- There exist $U \in \opens[X]$ such that $x \in U$ and $U\subseteq A$.
+ There exist $U \in \opens[X]$ such that $x \in U$ and $U\subseteq A$.
$U \subseteq \interior{A}{X}$.
Contradiction.
\end{subproof}
$\carrier[X]\setminus\interior{A}{X} \subseteq \closure{(\carrier[X]\setminus A)}{X}$.
- $\closure{(\carrier[X]\setminus A)}{X} \subseteq \carrier[X]\setminus\interior{A}{X}$.
+ $\closure{(\carrier[X]\setminus A)}{X} \subseteq \carrier[X]\setminus\interior{A}{X}$. % SLOW by \cref{setminus_subseteq,interior_is_open,complement_of_open_elem_closeds,subseteq_implies_setminus_supseteq,closure_is_minimal_closed_set}.
\end{proof}