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 ) ) |