Metamath Proof Explorer


Theorem shincli

Description: Closure of intersection of two subspaces. (Contributed by NM, 19-Oct-1999) (New usage is discouraged.)

Ref Expression
Hypotheses shincl.1
|- A e. SH
shincl.2
|- B e. SH
Assertion shincli
|- ( A i^i B ) e. SH

Proof

Step Hyp Ref Expression
1 shincl.1
 |-  A e. SH
2 shincl.2
 |-  B e. SH
3 1 elexi
 |-  A e. _V
4 2 elexi
 |-  B e. _V
5 3 4 intpr
 |-  |^| { A , B } = ( A i^i B )
6 1 2 pm3.2i
 |-  ( A e. SH /\ B e. SH )
7 3 4 prss
 |-  ( ( A e. SH /\ B e. SH ) <-> { A , B } C_ SH )
8 6 7 mpbi
 |-  { A , B } C_ SH
9 3 prnz
 |-  { A , B } =/= (/)
10 8 9 pm3.2i
 |-  ( { A , B } C_ SH /\ { A , B } =/= (/) )
11 10 shintcli
 |-  |^| { A , B } e. SH
12 5 11 eqeltrri
 |-  ( A i^i B ) e. SH