Transporting the kernel of a short exact complex #
noncomputable def
CategoryTheory.ShortComplex.sourceIsoKernelOfShortExactCompIso
{C : Type u}
[Category.{v, u} C]
[Abelian C]
(S : ShortComplex C)
(hS : S.ShortExact)
{Y : C}
(g : S.X₂ ⟶ Y)
(e : S.X₃ ≅ Y)
(h : CategoryStruct.comp S.g e.hom = g)
:
S.X₁ ≅ Limits.kernel g
If a short exact complex's second map is transported across an isomorphism of its target, its source remains a kernel of the transported map.