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authorSimon-Kor <52245124+Simon-Kor@users.noreply.github.com>2024-09-15 15:07:36 +0200
committerSimon-Kor <52245124+Simon-Kor@users.noreply.github.com>2024-09-15 15:07:36 +0200
commitb298295ac002785672a8b16dd09f9692d73f7a80 (patch)
tree9c03dde2cec2bca83927175819534cf53a7bd7c8 /library/topology/real-topological-space.tex
parent12f360a500d5edddf83afa121a5a08b6a6408815 (diff)
Issue at Fixing.
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+++ b/library/topology/real-topological-space.tex
@@ -17,10 +17,73 @@
$\topoBasisReals = \{ \epsBall{x}{\epsilon} \mid x \in \reals, \epsilon \in \realsplus\}$.
\end{definition}
-\begin{theorem}\label{reals_as_topo_space}
- Suppose $\opens[\reals] = \genOpens{\topoBasisReals}{\reals}$.
- Then $\reals$ is a topological space.
+\begin{axiom}\label{reals_carrier_reals}
+ $\carrier[\reals] = \reals$.
+\end{axiom}
+
+\begin{theorem}\label{topological_basis_reals_is_prebasis}
+ $\topoBasisReals$ is a topological prebasis for $\reals$.
\end{theorem}
\begin{proof}
- Omitted.
-\end{proof} \ No newline at end of file
+ We show that $\unions{\topoBasisReals} \subseteq \reals$.
+ \begin{subproof}
+ It suffices to show that for all $x \in \unions{\topoBasisReals}$ we have $x \in \reals$.
+ Fix $x \in \unions{\topoBasisReals}$.
+ \end{subproof}
+ We show that $\reals \subseteq \unions{\topoBasisReals}$.
+ \begin{subproof}
+ It suffices to show that for all $x \in \reals$ we have $x \in \unions{\topoBasisReals}$.
+ Fix $x \in \reals$.
+ \end{subproof}
+\end{proof}
+
+\begin{theorem}\label{topological_basis_reals_is_basis}
+ $\topoBasisReals$ is a topological basis for $\reals$.
+\end{theorem}
+\begin{proof}
+ $\topoBasisReals$ is a topological prebasis for $\reals$ by \cref{topological_basis_reals_is_prebasis}.
+ Let $B = \topoBasisReals$.
+ It suffices to show that for all $U \in B$ we have for all $V \in B$ we have for all $x$ such that $x \in U, V$ there exists $W\in B$ such that $x\in W\subseteq U, V$.
+ Fix $U \in B$.
+ Fix $V \in B$.
+ Fix $x \in U, V$.
+\end{proof}
+
+\begin{axiom}\label{topological_space_reals}
+ $\opens[\reals] = \genOpens{\topoBasisReals}{\reals}$.
+\end{axiom}
+
+\begin{theorem}\label{reals_is_topological_space}
+ $\reals$ is a topological space.
+\end{theorem}
+\begin{proof}
+ $\topoBasisReals$ is a topological basis for $\reals$.
+ Let $B = \topoBasisReals$.
+ We show that $\opens[\reals]$ is a family of subsets of $\carrier[\reals]$.
+ \begin{subproof}
+ It suffices to show that for all $A \in \opens[\reals]$ we have $A \subseteq \reals$.
+ Fix $A \in \opens[\reals]$.
+ Follows by \cref{powerset_elim,topological_space_reals,genopens}.
+ \end{subproof}
+ We show that $\reals \in\opens[\reals]$.
+ \begin{subproof}
+ $B$ covers $\reals$ by \cref{topological_prebasis_iff_covering_family,topological_basis}.
+ $\unions{B} \in \genOpens{B}{\reals}$.
+ $\reals \subseteq \unions{B}$.
+ \end{subproof}
+ We show that for all $A, B\in \opens[\reals]$ we have $A\inter B\in\opens[\reals]$.
+ \begin{subproof}
+ Follows by \cref{topological_space_reals,inters_in_genopens}.
+ \end{subproof}
+ We show that for all $F\subseteq \opens[\reals]$ we have $\unions{F}\in\opens[\reals]$.
+ \begin{subproof}
+ Follows by \cref{topological_space_reals,union_in_genopens}.
+ \end{subproof}
+ $\carrier[\reals] = \reals$.
+ Follows by \cref{topological_space}.
+\end{proof}
+
+\begin{proposition}\label{open_interval_is_open}
+ Suppose $a,b \in \reals$.
+ Then $\intervalopen{a}{b} \in \opens[\reals]$.
+\end{proposition} \ No newline at end of file