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Metamath Proof Explorer


Theorem ffrn

Description: A function maps to its range. (Contributed by Glauco Siliprandi, 3-Mar-2021)

Ref Expression
Assertion ffrn F : A B F : A ran F

Proof

Step Hyp Ref Expression
1 ffn F : A B F Fn A
2 dffn3 F Fn A F : A ran F
3 1 2 sylib F : A B F : A ran F