Metamath Proof Explorer


Theorem ffnov

Description: An operation maps to a class to which all values belong. (Contributed by NM, 7-Feb-2004)

Ref Expression
Assertion ffnov ⊢ F : A × B ⟶ C ↔ F Fn A × B ∧ ∀ x ∈ A ∀ y ∈ B x F y ∈ C

Proof

Step Hyp Ref Expression
1 ffnfv ⊢ F : A × B ⟶ C ↔ F Fn A × B ∧ ∀ w ∈ A × B F ⁡ w ∈ C
2 fveq2 ⊢ w = x y → F ⁡ w = F ⁡ x y
3 df-ov ⊢ x F y = F ⁡ x y
4 2 3 eqtr4di ⊢ w = x y → F ⁡ w = x F y
5 4 eleq1d ⊢ w = x y → F ⁡ w ∈ C ↔ x F y ∈ C
6 5 ralxp ⊢ ∀ w ∈ A × B F ⁡ w ∈ C ↔ ∀ x ∈ A ∀ y ∈ B x F y ∈ C
7 6 anbi2i ⊢ F Fn A × B ∧ ∀ w ∈ A × B F ⁡ w ∈ C ↔ F Fn A × B ∧ ∀ x ∈ A ∀ y ∈ B x F y ∈ C
8 1 7 bitri ⊢ F : A × B ⟶ C ↔ F Fn A × B ∧ ∀ x ∈ A ∀ y ∈ B x F y ∈ C