Metamath Proof Explorer


Theorem rnffi

Description: The range of a function with finite domain is finite. (Contributed by Glauco Siliprandi, 11-Dec-2019)

Ref Expression
Assertion rnffi ⊢ F : A ⟶ B ∧ A ∈ Fin → ran ⁡ F ∈ Fin

Proof

Step Hyp Ref Expression
1 ffi ⊢ F : A ⟶ B ∧ A ∈ Fin → F ∈ Fin
2 rnfi ⊢ F ∈ Fin → ran ⁡ F ∈ Fin
3 1 2 syl ⊢ F : A ⟶ B ∧ A ∈ Fin → ran ⁡ F ∈ Fin