Metamath Proof Explorer


Theorem pwexg

Description: Power set axiom expressed in class notation, with the sethood requirement as an antecedent. (Contributed by NM, 30-Oct-2003)

Ref Expression
Assertion pwexg ⊢ A ∈ V → 𝒫 A ∈ V

Proof

Step Hyp Ref Expression
1 pweq ⊢ x = A → 𝒫 x = 𝒫 A
2 1 eleq1d ⊢ x = A → 𝒫 x ∈ V ↔ 𝒫 A ∈ V
3 vpwex ⊢ 𝒫 x ∈ V
4 2 3 vtoclg ⊢ A ∈ V → 𝒫 A ∈ V