English
Equality of Arrow morphisms is determined by their components and whiskers.
Русский
Равенство морфизмов стрелы определяется компонентами и whisker-операциями.
LaTeX
$$$\forall f,g : Arrow\ T\; (h_1: f.left = g.left) (h_2: f.right = g.right) (h_3: f.hom = eqToHom h_1 ≫ g.hom ≫ eqToHom h_2^{{\cdot}}) \Rightarrow f = g$$$
Lean4
theorem ext {f g : Arrow T} (h₁ : f.left = g.left) (h₂ : f.right = g.right)
(h₃ : f.hom = eqToHom h₁ ≫ g.hom ≫ eqToHom h₂.symm) : f = g :=
(mk_eq_mk_iff _ _).2 (by simp_all)