Theorem bj-nfsab1

Description: Remove dependency on ax-13 from nfsab1 . UPDATE / TODO: nfsab1 does not use ax-13 either anymore; bj-nfsab1 is shorter than nfsab1 but uses ax-12 . (Contributed by BJ, 23-Jun-2019) (Proof modification is discouraged.)

	Ref	Expression
Assertion	bj-nfsab1	⊢ 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 }