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 φ → ψ → φ → ∃ x ψ

Proof

Step Hyp Ref Expression
1 bj-nnfa ⊢ Ⅎ' x φ → φ → ∀ x φ
2 bj-spimenfa ⊢ φ → ∀ x φ → ∃ x φ → ψ → φ → ∃ x ψ
3 1 2 syl ⊢ Ⅎ' x φ → ∃ x φ → ψ → φ → ∃ x ψ