Metamath Proof Explorer


Theorem pwuninelOLD

Description: Obsolete version of pwuninel as of 10-Jun-2026. (Contributed by NM, 27-Jun-2008) (Proof shortened by Mario Carneiro, 23-Dec-2016) (Proof modification is discouraged.) (New usage is discouraged.)

Ref Expression
Assertion pwuninelOLD ¬ 𝒫 ∪ 𝐴 ∈ 𝐴

Proof

Step Hyp Ref Expression
1 pwexr ⊢ ( 𝒫 ∪ 𝐴 ∈ 𝐴 → ∪ 𝐴 ∈ V )
2 pwuninel2 ⊢ ( ∪ 𝐴 ∈ V → ¬ 𝒫 ∪ 𝐴 ∈ 𝐴 )
3 1 2 syl ⊢ ( 𝒫 ∪ 𝐴 ∈ 𝐴 → ¬ 𝒫 ∪ 𝐴 ∈ 𝐴 )
4 id ⊢ ( ¬ 𝒫 ∪ 𝐴 ∈ 𝐴 → ¬ 𝒫 ∪ 𝐴 ∈ 𝐴 )
5 3 4 pm2.61i ⊢ ¬ 𝒫 ∪ 𝐴 ∈ 𝐴