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