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:ABACFV

Proof

Step Hyp Ref Expression
1 ffn F:ABFFnA
2 fnex FFnAACFV
3 1 2 sylan F:ABACFV