proposition: Lemma embed_project_id : forall m, project (embed m) = m.
proof: Proof. intro. cbv. rewrite monoid_law2 //. Qed.
imports: Coq(ssreflect ssrfun ssrbool List) Coq(FunctionalExtensionality) Coq(Relation_Definitions Morphisms) Mon(SPropBase SPropMonadicStructures)