Theorem nfcvd

Description: If x is disjoint from A , then x is not free in A . (Contributed by Mario Carneiro, 7-Oct-2016)

	Ref	Expression
Assertion	nfcvd	|- ( ph -> F/_ x A )

Proof

Step	Hyp	Ref	Expression
1		nfcv	|- F/_ x A
2	1	a1i	|- ( ph -> F/_ x A )