English
The effective epi structure provides a unique desc map: if m: X → W satisfies f ≫ m = e, then m = EffectiveEpi.desc f e h.
Русский
Структура эффективной эпиморфии задаёт единственный desc: если m: X → W удовлетворяет f ≫ m = e, то m = EffectiveEpi.desc f e h.
LaTeX
$$m = EffectiveEpi.desc f e h$$
Lean4
theorem uniq {X Y W : C} (f : Y ⟶ X) [EffectiveEpi f] (e : Y ⟶ W)
(h : ∀ {Z : C} (g₁ g₂ : Z ⟶ Y), g₁ ≫ f = g₂ ≫ f → g₁ ≫ e = g₂ ≫ e) (m : X ⟶ W) (hm : f ≫ m = e) :
m = EffectiveEpi.desc f e h :=
(EffectiveEpi.getStruct f).uniq e h _ hm