Metamath Proof Explorer


Theorem wl-ax11-lem7

Description: Lemma. (Contributed by Wolf Lammen, 30-Jun-2019)

Ref Expression
Assertion wl-ax11-lem7 ( ∀ 𝑥 ( ¬ ∀ 𝑥 𝑥 = 𝑦𝜑 ) ↔ ( ¬ ∀ 𝑥 𝑥 = 𝑦 ∧ ∀ 𝑥 𝜑 ) )

Proof

Step Hyp Ref Expression
1 nfna1 𝑥 ¬ ∀ 𝑥 𝑥 = 𝑦
2 1 19.28 ( ∀ 𝑥 ( ¬ ∀ 𝑥 𝑥 = 𝑦𝜑 ) ↔ ( ¬ ∀ 𝑥 𝑥 = 𝑦 ∧ ∀ 𝑥 𝜑 ) )