Theorem bj-nfs1v

Description: Version of nfsb2 with a disjoint variable condition, which does not require ax-13 , and removal of ax-13 from nfs1v . (Contributed by BJ, 24-Jun-2019) (Proof modification is discouraged.)

	Ref	Expression
Assertion	bj-nfs1v	$$⊢Ⅎx\left[y/x\right]\phi$$

Proof

Step	Hyp	Ref	Expression
1		bj-hbs1	$$⊢\left[y/x\right]\phi \to \forall x\left[y/x\right]\phi$$
2	1	nf5i	$$⊢Ⅎx\left[y/x\right]\phi$$