English
If φ: K → L is a morphism with φ.f i epi for all i and the relation Rel(i,j) does not hold for any j, then the homology map is epi at i.
Русский
Если φ: K → L имеет эпиморфизм на каждом компоненте и отсутствуют пары i,j с отношением Rel, то homologyMap φ i является эпиморфизмом.
LaTeX
$$$$ \\text{epi}(\\mathrm{homologyMap}(\\varphi,i)) $$$$
Lean4
theorem mono_homologyMap_of_mono_of_not_rel (φ : K ⟶ L) (j : ι) [K.HasHomology j] [L.HasHomology j] [Mono (φ.f j)]
(hj : ∀ i, ¬c.Rel i j) : Mono (homologyMap φ j) :=
((MorphismProperty.monomorphisms C).arrow_mk_iso_iff
(Arrow.isoMk (K.isoHomologyπ _ j rfl (shape _ _ _ (by tauto)))
(L.isoHomologyπ _ j rfl (shape _ _ _ (by tauto))))).1
(MorphismProperty.monomorphisms.infer_property (cyclesMap φ j))