English
Composition of mapDomain along f and g equals mapDomain along f ∘ g.
Русский
Сложение mapDomain по f и по g эквивалентно mapDomain по f ∘ g.
LaTeX
$$$\\operatorname{mapDomain.addMonoidHom} (f \\circ g) = (\\operatorname{mapDomain.addMonoidHom} f) \\cdot (\\operatorname{mapDomain.addMonoidHom} g).$$$
Lean4
theorem addMonoidHom_comp (f : β → γ) (g : α → β) :
(mapDomain.addMonoidHom (f ∘ g) : (α →₀ M) →+ γ →₀ M) =
(mapDomain.addMonoidHom f).comp (mapDomain.addMonoidHom g) :=
AddMonoidHom.ext fun _ => mapDomain_comp