Theorem nfa1-o

Description: x is not free in A. x ph . (Contributed by Mario Carneiro, 11-Aug-2016) (Proof modification is discouraged.) (New usage is discouraged.)

	Ref	Expression
Assertion	nfa1-o	$$⊢Ⅎx\forall x\phi$$

Proof

Step	Hyp	Ref	Expression
1		hba1-o	$$⊢\forall x\phi \to \forall x\forall x\phi$$
2	1	nf5i	$$⊢Ⅎx\forall x\phi$$