Database
SUPPLEMENTARY MATERIAL (USERS' MATHBOXES)
Mathbox for BJ
First-order logic
Adding ax-5
bj-cbveximi
Metamath Proof Explorer
Description: An equality-free general instance of one half of a precise form of
bj-cbvex . (Contributed by BJ , 12-Mar-2023)
(Proof modification is discouraged.)
Ref
Expression
Hypotheses
bj-cbvalimi.maj
⊢ ( 𝜒 → ( 𝜑 → 𝜓 ) )
bj-cbveximi.denote
⊢ ∀ 𝑥 ∃ 𝑦 𝜒
Assertion
bj-cbveximi
⊢ ( ∃ 𝑥 𝜑 → ∃ 𝑦 𝜓 )
Proof
Step
Hyp
Ref
Expression
1
bj-cbvalimi.maj
⊢ ( 𝜒 → ( 𝜑 → 𝜓 ) )
2
bj-cbveximi.denote
⊢ ∀ 𝑥 ∃ 𝑦 𝜒
3
1
gen2
⊢ ∀ 𝑥 ∀ 𝑦 ( 𝜒 → ( 𝜑 → 𝜓 ) )
4
bj-cbvexim
⊢ ( ∀ 𝑥 ∃ 𝑦 𝜒 → ( ∀ 𝑥 ∀ 𝑦 ( 𝜒 → ( 𝜑 → 𝜓 ) ) → ( ∃ 𝑥 𝜑 → ∃ 𝑦 𝜓 ) ) )
5
2 3 4
mp2
⊢ ( ∃ 𝑥 𝜑 → ∃ 𝑦 𝜓 )