Theorem hbal

Description: If x is not free in ph , it is not free in A. y ph . (Contributed by NM, 12-Mar-1993)

	Ref	Expression
Hypothesis	hbal.1	|- ( ph -> A. x ph )
Assertion	hbal	|- ( A. y ph -> A. x A. y ph )

Proof

Step	Hyp	Ref	Expression
1		hbal.1	|- ( ph -> A. x ph )
2	1	alimi	|- ( A. y ph -> A. y A. x ph )
3		ax-11	|- ( A. y A. x ph -> A. x A. y ph )
4	2 3	syl	|- ( A. y ph -> A. x A. y ph )