Theorem nfsab1OLD

Description: Obsolete version of nfsab1 as of 20-Sep-2023. (Contributed by Mario Carneiro, 11-Aug-2016) (Proof modification is discouraged.) (New usage is discouraged.)

	Ref	Expression
Assertion	nfsab1OLD	⊢ Ⅎ 𝑥 𝑦 ∈ { 𝑥 ∣ 𝜑 }

Proof

Step	Hyp	Ref	Expression
1		hbab1	⊢ ( 𝑦 ∈ { 𝑥 ∣ 𝜑 } → ∀ 𝑥 𝑦 ∈ { 𝑥 ∣ 𝜑 } )
2	1	nf5i	⊢ Ⅎ 𝑥 𝑦 ∈ { 𝑥 ∣ 𝜑 }