English
Two one-step ComposableArrows F and G are equal if their left and right inputs agree and their central morphism is determined by the equality of those components.
Русский
Два одноступенчатых ComposableArrows равны, если их левая и правая части равны и центральный морфизм задан равенством соответствующих компонент.
LaTeX
$$$\forall F,G : ComposableArrows\ C\ 1, \ (F.left = G.left) \land (F.right = G.right) \land (F.hom = eqToHom left ≫ G.hom ≫ eqToHom right.symm) \Rightarrow F = G$$$
Lean4
theorem ext₀ {F G : ComposableArrows C 0} (h : F.obj' 0 = G.obj 0) : F = G :=
ext
(fun i =>
match i with
| ⟨0, _⟩ => h)
(fun i hi => by simp at hi)