Metamath Proof Explorer


Theorem fthi

Description: The morphism map of a faithful functor is an injection. (Contributed by Mario Carneiro, 27-Jan-2017)

Ref Expression
Hypotheses isfth.b ⊢ B = Base C
isfth.h ⊢ H = Hom ⁡ C
isfth.j ⊢ J = Hom ⁡ D
fthf1.f ⊢ φ → F C Faith D G
fthf1.x ⊢ φ → X ∈ B
fthf1.y ⊢ φ → Y ∈ B
fthi.r ⊢ φ → R ∈ X H Y
fthi.s ⊢ φ → S ∈ X H Y
Assertion fthi ⊢ φ → X G Y ⁡ R = X G Y ⁡ S ↔ R = S

Proof

Step Hyp Ref Expression
1 isfth.b ⊢ B = Base C
2 isfth.h ⊢ H = Hom ⁡ C
3 isfth.j ⊢ J = Hom ⁡ D
4 fthf1.f ⊢ φ → F C Faith D G
5 fthf1.x ⊢ φ → X ∈ B
6 fthf1.y ⊢ φ → Y ∈ B
7 fthi.r ⊢ φ → R ∈ X H Y
8 fthi.s ⊢ φ → S ∈ X H Y
9 1 2 3 4 5 6 fthf1 ⊢ φ → X G Y : X H Y ⟶ 1-1 F ⁡ X J F ⁡ Y
10 f1fveq ⊢ X G Y : X H Y ⟶ 1-1 F ⁡ X J F ⁡ Y ∧ R ∈ X H Y ∧ S ∈ X H Y → X G Y ⁡ R = X G Y ⁡ S ↔ R = S
11 9 7 8 10 syl12anc ⊢ φ → X G Y ⁡ R = X G Y ⁡ S ↔ R = S