Theorem chjvali

Description: Value of join in CH . (Contributed by NM, 9-Aug-2000) (New usage is discouraged.)

	Ref	Expression
Hypotheses	chjval.1	|- A e. CH
	chjval.2	|- B e. CH
Assertion	chjvali	|- ( A vH B ) = ( _|_ ` ( _|_ ` ( A u. B ) ) )

Proof

Step	Hyp	Ref	Expression
1		chjval.1	|- A e. CH
2		chjval.2	|- B e. CH
3		chjval	|- ( ( A e. CH /\ B e. CH ) -> ( A vH B ) = ( _|_ ` ( _|_ ` ( A u. B ) ) ) )
4	1 2 3	mp2an	|- ( A vH B ) = ( _|_ ` ( _|_ ` ( A u. B ) ) )