English
Composition of zeroHoms is respected by mapRange: mapRange.zeroHom (f.comp f₂) equals (mapRange.zeroHom f).comp (mapRange.zeroHom f₂).
Русский
Композиция нулевых гомоморфизмов сохраняется через mapRange: mapRange.zeroHom (f.comp f₂) = (mapRange.zeroHom f) .comp (mapRange.zeroHom f₂).
LaTeX
$$mapRange.zeroHom (f.comp f₂) = (mapRange.zeroHom f).comp (mapRange.zeroHom f₂)$$
Lean4
theorem zeroHom_comp (f : ZeroHom N P) (f₂ : ZeroHom M N) :
(mapRange.zeroHom (f.comp f₂) : ZeroHom (α →₀ _) _) = (mapRange.zeroHom f).comp (mapRange.zeroHom f₂) :=
ZeroHom.ext <| mapRange_comp f (map_zero f) f₂ (map_zero f₂) (by simp only [comp_apply, map_zero])