Metamath Proof Explorer


Theorem bj-19.37im

Description: One direction of 19.37 from the same axioms as 19.37imv . (Contributed by BJ, 2-Dec-2023)

Ref Expression
Assertion bj-19.37im ( Ⅎ' 𝑥 𝜑 → ( ∃ 𝑥 ( 𝜑𝜓 ) → ( 𝜑 → ∃ 𝑥 𝜓 ) ) )

Proof

Step Hyp Ref Expression
1 19.35 ( ∃ 𝑥 ( 𝜑𝜓 ) ↔ ( ∀ 𝑥 𝜑 → ∃ 𝑥 𝜓 ) )
2 bj-nnfa ( Ⅎ' 𝑥 𝜑 → ( 𝜑 → ∀ 𝑥 𝜑 ) )
3 2 imim1d ( Ⅎ' 𝑥 𝜑 → ( ( ∀ 𝑥 𝜑 → ∃ 𝑥 𝜓 ) → ( 𝜑 → ∃ 𝑥 𝜓 ) ) )
4 1 3 syl5bi ( Ⅎ' 𝑥 𝜑 → ( ∃ 𝑥 ( 𝜑𝜓 ) → ( 𝜑 → ∃ 𝑥 𝜓 ) ) )