Description: One direction of 19.37v that can be proven without ax-6 . (Contributed by Rohan Ridenour, 16-Apr-2022)
Ref | Expression | ||
---|---|---|---|
Assertion | 19.37imv | ⊢ ( ∃ 𝑥 ( 𝜑 → 𝜓 ) → ( 𝜑 → ∃ 𝑥 𝜓 ) ) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | ax-5 | ⊢ ( 𝜑 → ∀ 𝑥 𝜑 ) | |
2 | 19.35 | ⊢ ( ∃ 𝑥 ( 𝜑 → 𝜓 ) ↔ ( ∀ 𝑥 𝜑 → ∃ 𝑥 𝜓 ) ) | |
3 | 2 | biimpi | ⊢ ( ∃ 𝑥 ( 𝜑 → 𝜓 ) → ( ∀ 𝑥 𝜑 → ∃ 𝑥 𝜓 ) ) |
4 | 1 3 | syl5 | ⊢ ( ∃ 𝑥 ( 𝜑 → 𝜓 ) → ( 𝜑 → ∃ 𝑥 𝜓 ) ) |