Theorem isseti

Description: A way to say " A is a set" (inference form). (Contributed by NM, 24-Jun-1993) Remove dependencies on axioms. (Revised by BJ, 13-Jul-2019)

	Ref	Expression
Hypothesis	isseti.1	⊢ 𝐴 ∈ V
Assertion	isseti	⊢ ∃ 𝑥 𝑥 = 𝐴

Proof

Step	Hyp	Ref	Expression
1		isseti.1	⊢ 𝐴 ∈ V
2		elisset	⊢ ( 𝐴 ∈ V → ∃ 𝑥 𝑥 = 𝐴 )
3	1 2	ax-mp	⊢ ∃ 𝑥 𝑥 = 𝐴