English
If two linear maps from relations.Quotient agree on all generators given by toQuotient (Finsupp.single g 1), they are equal.
Русский
Если два линейных отображения из relations.Quotient совпадают на всех генераторах, заданных toQuotient (Finsupp.single g 1), они равны.
LaTeX
$$$\\forall g,\\ f( relations.toQuotient(\\mathrm{Finsupp.single} g\\ 1)) = f'( relations.toQuotient(\\mathrm{Finsupp.single} g\\ 1)) \\Rightarrow f = f'.$$$
Lean4
@[ext]
theorem linearMap_ext {M : Type v} [AddCommGroup M] [Module A M] {f f' : relations.Quotient →ₗ[A] M}
(h :
∀ (g : relations.G),
f (relations.toQuotient (Finsupp.single g 1)) = f' (relations.toQuotient (Finsupp.single g 1))) :
f = f' :=
Submodule.linearMap_qext _ (Finsupp.lhom_ext' (fun g ↦ LinearMap.ext_ring (h g)))