Metamath Proof Explorer


Theorem ifexd

Description: Existence of the conditional operator (deduction form). (Contributed by SN, 26-Jul-2024)

Ref Expression
Hypotheses ifexd.1 ⊢ φ → A ∈ V
ifexd.2 ⊢ φ → B ∈ W
Assertion ifexd ⊢ φ → if ψ A B ∈ V

Proof

Step Hyp Ref Expression
1 ifexd.1 ⊢ φ → A ∈ V
2 ifexd.2 ⊢ φ → B ∈ W
3 1 elexd ⊢ φ → A ∈ V
4 2 elexd ⊢ φ → B ∈ V
5 3 4 ifcld ⊢ φ → if ψ A B ∈ V