Metamath Proof Explorer


Theorem chdmj4i

Description: De Morgan's law for join in a Hilbert lattice. (Contributed by NM, 21-Jun-2004) (New usage is discouraged.)

Ref Expression
Hypotheses ch0le.1
|- A e. CH
chjcl.2
|- B e. CH
Assertion chdmj4i
|- ( _|_ ` ( ( _|_ ` A ) vH ( _|_ ` B ) ) ) = ( A i^i B )

Proof

Step Hyp Ref Expression
1 ch0le.1
 |-  A e. CH
2 chjcl.2
 |-  B e. CH
3 2 choccli
 |-  ( _|_ ` B ) e. CH
4 1 3 chdmj2i
 |-  ( _|_ ` ( ( _|_ ` A ) vH ( _|_ ` B ) ) ) = ( A i^i ( _|_ ` ( _|_ ` B ) ) )
5 2 pjococi
 |-  ( _|_ ` ( _|_ ` B ) ) = B
6 5 ineq2i
 |-  ( A i^i ( _|_ ` ( _|_ ` B ) ) ) = ( A i^i B )
7 4 6 eqtri
 |-  ( _|_ ` ( ( _|_ ` A ) vH ( _|_ ` B ) ) ) = ( A i^i B )