Description: Closed form of nexdv . (Contributed by BJ, 20-Oct-2019)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | bj-nexdvt | ⊢ ( ∀ 𝑥 ( 𝜑 → ¬ 𝜓 ) → ( 𝜑 → ¬ ∃ 𝑥 𝜓 ) ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | nfv | ⊢ Ⅎ 𝑥 𝜑 | |
| 2 | bj-nexdt | ⊢ ( Ⅎ 𝑥 𝜑 → ( ∀ 𝑥 ( 𝜑 → ¬ 𝜓 ) → ( 𝜑 → ¬ ∃ 𝑥 𝜓 ) ) ) | |
| 3 | 1 2 | ax-mp | ⊢ ( ∀ 𝑥 ( 𝜑 → ¬ 𝜓 ) → ( 𝜑 → ¬ ∃ 𝑥 𝜓 ) ) |