English
If j and k are monoid homomorphisms from S to a monoid P and j ∘ algebraMap_R_S = k ∘ algebraMap_R_S, then j = k.
Русский
Если j и k — моноид-гомоморфизмы S→P и j ∘ algebraMap_R_S = k ∘ algebraMap_R_S, тогда j = k.
LaTeX
$$$ \\forall j,k : S \\to P,\\; j \\circ (\\mathrm{algebraMap}_{R,S}) = k \\circ (\\mathrm{algebraMap}_{R,S}) \\Rightarrow j = k. $$$
Lean4
/-- See note [partially-applied ext lemmas] -/
theorem monoidHom_ext {P : Type*} [Monoid P] ⦃j k : S →* P⦄
(h : j.comp (algebraMap R S : R →* S) = k.comp (algebraMap R S)) : j = k :=
(toLocalizationMap M S).epic_of_localizationMap h