Metamath Proof Explorer


Theorem funbrafvb

Description: Equivalence of function value and binary relation, analogous to funbrfvb . (Contributed by Alexander van der Vekens, 25-May-2017)

Ref Expression
Assertion funbrafvb ( ( Fun 𝐹 ∧ 𝐴 ∈ dom 𝐹 ) → ( ( 𝐹 ''' 𝐴 ) = 𝐵 ↔ 𝐴 𝐹 𝐵 ) )

Proof

Step Hyp Ref Expression
1 funfn ⊢ ( Fun 𝐹 ↔ 𝐹 Fn dom 𝐹 )
2 fnbrafvb ⊢ ( ( 𝐹 Fn dom 𝐹 ∧ 𝐴 ∈ dom 𝐹 ) → ( ( 𝐹 ''' 𝐴 ) = 𝐵 ↔ 𝐴 𝐹 𝐵 ) )
3 1 2 sylanb ⊢ ( ( Fun 𝐹 ∧ 𝐴 ∈ dom 𝐹 ) → ( ( 𝐹 ''' 𝐴 ) = 𝐵 ↔ 𝐴 𝐹 𝐵 ) )