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authoradelon <22380201+adelon@users.noreply.github.com>2024-05-28 17:09:06 +0200
committeradelon <22380201+adelon@users.noreply.github.com>2024-05-28 17:09:06 +0200
commit719bb860942fc1134ad4a4ae55db2713cd100f1a (patch)
tree95e58b26f86873741a7e8d85db84137012e1de11 /library/set.tex
parenta6a83d15a866d7ba40dfc6b733cea14314da3b25 (diff)
Pow closed under binary intersection
Diffstat (limited to 'library/set.tex')
-rw-r--r--library/set.tex13
1 files changed, 5 insertions, 8 deletions
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 $U\inter V\in T$.