Metamath Proof Explorer


Theorem rexlimdvv

Description: Inference from Theorem 19.23 of Margaris p. 90. (Restricted quantifier version.) (Contributed by NM, 22-Jul-2004)

Ref Expression
Hypothesis rexlimdvv.1 ⊢ φ → x ∈ A ∧ y ∈ B → ψ → χ
Assertion rexlimdvv ⊢ φ → ∃ x ∈ A ∃ y ∈ B ψ → χ

Proof

Step Hyp Ref Expression
1 rexlimdvv.1 ⊢ φ → x ∈ A ∧ y ∈ B → ψ → χ
2 1 expdimp ⊢ φ ∧ x ∈ A → y ∈ B → ψ → χ
3 2 rexlimdv ⊢ φ ∧ x ∈ A → ∃ y ∈ B ψ → χ
4 3 rexlimdva ⊢ φ → ∃ x ∈ A ∃ y ∈ B ψ → χ