Theorem nfab1

Description: Bound-variable hypothesis builder for a class abstraction. (Contributed by Mario Carneiro, 11-Aug-2016)

	Ref	Expression
Assertion	nfab1	⊢ Ⅎ 𝑥 { 𝑥 ∣ 𝜑 }

Proof

Step	Hyp	Ref	Expression
1		nfsab1	⊢ Ⅎ 𝑥 𝑦 ∈ { 𝑥 ∣ 𝜑 }
2	1	nfci	⊢ Ⅎ 𝑥 { 𝑥 ∣ 𝜑 }