Theorem nf5i

Description: Deduce that x is not free in ph from the definition. (Contributed by Mario Carneiro, 11-Aug-2016)

	Ref	Expression
Hypothesis	nf5i.1	|- ( ph -> A. x ph )
Assertion	nf5i	|- F/ x ph

Proof

Step	Hyp	Ref	Expression
1		nf5i.1	|- ( ph -> A. x ph )
2		nf5-1	|- ( A. x ( ph -> A. x ph ) -> F/ x ph )
3	2 1	mpg	|- F/ x ph