From b298295ac002785672a8b16dd09f9692d73f7a80 Mon Sep 17 00:00:00 2001 From: Simon-Kor <52245124+Simon-Kor@users.noreply.github.com> Date: Sun, 15 Sep 2024 15:07:36 +0200 Subject: Issue at Fixing. In Line 49 in real-topological-space.tex the Fix can't be processed. --- library/topology/real-topological-space.tex | 73 +++++++++++++++++++++++++++-- 1 file changed, 68 insertions(+), 5 deletions(-) (limited to 'library/topology/real-topological-space.tex') diff --git a/library/topology/real-topological-space.tex b/library/topology/real-topological-space.tex index 239965c..db46732 100644 --- a/library/topology/real-topological-space.tex +++ 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 -- cgit v1.2.3