From 719bb860942fc1134ad4a4ae55db2713cd100f1a Mon Sep 17 00:00:00 2001 From: adelon <22380201+adelon@users.noreply.github.com> Date: Tue, 28 May 2024 17:09:06 +0200 Subject: Pow closed under binary intersection --- library/set.tex | 13 +++++-------- 1 file changed, 5 insertions(+), 8 deletions(-) (limited to 'library/set.tex') diff --git a/library/set.tex b/library/set.tex index fcd2642..2fd18ea 100644 --- a/library/set.tex +++ b/library/set.tex @@ -551,14 +551,6 @@ The $\operatorname{\textsf{cons}}$ operation is determined by the following axio Follows by set extensionality. \end{proof} -\begin{proposition}\label{inter_subseteq_left} - $A\inter B\subseteq A$. -\end{proposition} - -\begin{proposition}\label{inter_subseteq_right} - $A\inter B\subseteq B$. -\end{proposition} - \begin{proposition}\label{inter_emptyset} $A\inter\emptyset = \emptyset$. \end{proposition} @@ -620,6 +612,11 @@ The $\operatorname{\textsf{cons}}$ operation is determined by the following axio Follows by set extensionality. \end{proof} +\begin{proposition}\label{inter_subseteq} + Suppose $A,B\subseteq C$. + Then $A\inter B\subseteq C$. +\end{proposition} + \begin{abbreviation}\label{closedunderinter} $T$ is closed under binary intersections iff for every $U,V\in T$ we have $U\inter V\in T$. -- cgit v1.2.3