Description: Lemma. (Contributed by Wolf Lammen, 30-Jun-2019)
Ref | Expression | ||
---|---|---|---|
Assertion | wl-ax11-lem7 | ⊢ ( ∀ 𝑥 ( ¬ ∀ 𝑥 𝑥 = 𝑦 ∧ 𝜑 ) ↔ ( ¬ ∀ 𝑥 𝑥 = 𝑦 ∧ ∀ 𝑥 𝜑 ) ) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | nfna1 | ⊢ Ⅎ 𝑥 ¬ ∀ 𝑥 𝑥 = 𝑦 | |
2 | 1 | 19.28 | ⊢ ( ∀ 𝑥 ( ¬ ∀ 𝑥 𝑥 = 𝑦 ∧ 𝜑 ) ↔ ( ¬ ∀ 𝑥 𝑥 = 𝑦 ∧ ∀ 𝑥 𝜑 ) ) |