Metamath Proof Explorer


Theorem fex

Description: If the domain of a mapping is a set, the function is a set. (Contributed by NM, 3-Oct-1999)

Ref Expression
Assertion fex ⊢ F : A ⟶ B ∧ A ∈ C → F ∈ V

Proof

Step Hyp Ref Expression
1 ffn ⊢ F : A ⟶ B → F Fn A
2 fnex ⊢ F Fn A ∧ A ∈ C → F ∈ V
3 1 2 sylan ⊢ F : A ⟶ B ∧ A ∈ C → F ∈ V