Metamath Proof Explorer


Theorem fcdmvafv2v

Description: If the codomain of a function is a set, the alternate function value is always also a set. (Contributed by AV, 4-Sep-2022)

Ref Expression
Assertion fcdmvafv2v ( ( 𝐹 : 𝐴 ⟶ 𝐵 ∧ 𝐵 ∈ 𝑉 ) → ( 𝐹 '''' 𝐶 ) ∈ V )

Proof

Step Hyp Ref Expression
1 df-f ⊢ ( 𝐹 : 𝐴 ⟶ 𝐵 ↔ ( 𝐹 Fn 𝐴 ∧ ran 𝐹 ⊆ 𝐵 ) )
2 ssexg ⊢ ( ( ran 𝐹 ⊆ 𝐵 ∧ 𝐵 ∈ 𝑉 ) → ran 𝐹 ∈ V )
3 2 ex ⊢ ( ran 𝐹 ⊆ 𝐵 → ( 𝐵 ∈ 𝑉 → ran 𝐹 ∈ V ) )
4 1 3 simplbiim ⊢ ( 𝐹 : 𝐴 ⟶ 𝐵 → ( 𝐵 ∈ 𝑉 → ran 𝐹 ∈ V ) )
5 4 imp ⊢ ( ( 𝐹 : 𝐴 ⟶ 𝐵 ∧ 𝐵 ∈ 𝑉 ) → ran 𝐹 ∈ V )
6 afv2ex ⊢ ( ran 𝐹 ∈ V → ( 𝐹 '''' 𝐶 ) ∈ V )
7 5 6 syl ⊢ ( ( 𝐹 : 𝐴 ⟶ 𝐵 ∧ 𝐵 ∈ 𝑉 ) → ( 𝐹 '''' 𝐶 ) ∈ V )