Theorem nfvd

Description: nfv with antecedent. Useful in proofs of deduction versions of bound-variable hypothesis builders such as nfimd . (Contributed by Mario Carneiro, 6-Oct-2016)

	Ref	Expression
Assertion	nfvd	⊢ ( 𝜑 → Ⅎ 𝑥 𝜓 )

Proof

Step	Hyp	Ref	Expression
1		nfv	⊢ Ⅎ 𝑥 𝜓
2	1	a1i	⊢ ( 𝜑 → Ⅎ 𝑥 𝜓 )