English
Equality of mk-factors yields an isomorphism between the corresponding subobject images.
Русский
Равенство mk-факторов порождает изоморфизм соответствующих образов подобъектов.
LaTeX
$$$\text{isoOfEqMk } \;X:\ Subobject B \to A : (X = mk f) \Rightarrow (X : C) \cong A$$$
Lean4
/-- An equality of subobjects gives an isomorphism of the corresponding objects.
(One could use `underlying.mapIso (eqToIso h))` here, but this is more readable.) -/
@[simps]
def isoOfEq {B : C} (X Y : Subobject B) (h : X = Y) : (X : C) ≅ (Y : C)
where
hom := ofLE _ _ h.le
inv := ofLE _ _ h.ge