Theorem vexOLD

Description: Obsolete version of vex as of 4-Sep-2024. (Contributed by NM, 26-May-1993) Remove use of ax-12 . (Revised by SN, 28-Aug-2023) (Proof modification is discouraged.) (New usage is discouraged.)

	Ref	Expression
Assertion	vexOLD	⊢ 𝑥 ∈ V

Proof

Step	Hyp	Ref	Expression
1		equid	⊢ 𝑥 = 𝑥
2	1	vexw	⊢ 𝑥 ∈ { 𝑥 ∣ 𝑥 = 𝑥 }
3		df-v	⊢ V = { 𝑥 ∣ 𝑥 = 𝑥 }
4	2 3	eleqtrri	⊢ 𝑥 ∈ V