Theorem shjcomi

Description: Commutative law for join in SH . (Contributed by NM, 19-Oct-1999) (New usage is discouraged.)

	Ref	Expression
Hypotheses	shincl.1	|- A e. SH
	shincl.2	|- B e. SH
Assertion	shjcomi	|- ( A vH B ) = ( B vH A )

Proof

Step	Hyp	Ref	Expression
1		shincl.1	|- A e. SH
2		shincl.2	|- B e. SH
3		shjcom	|- ( ( A e. SH /\ B e. SH ) -> ( A vH B ) = ( B vH A ) )
4	1 2 3	mp2an	|- ( A vH B ) = ( B vH A )