English
There is a natural R-module structure on the hom-set Hom(X, Y) compatible with composition and addition of morphisms.
Русский
Существует естественное R-модульное строение множества гомоморфизмов между комплексами, совместимое с сложением и композициями.
LaTeX
$$$\\text{Hom}(X,Y)$ is a module over R with operations defined componentwise on morphisms.$$
Lean4
instance (X Y : HomologicalComplex C c) : Module R (X ⟶ Y)
where
one_smul a := by cat_disch
smul_zero := by cat_disch
smul_add := by cat_disch
zero_smul := by cat_disch
add_smul _ _ _ := by ext; apply add_smul
mul_smul _ _ _ := by ext; apply mul_smul