proposition: Lemma fsinjectiveP f : reflect (injective f) (fsinjectiveb f).
proof: Proof. apply: equivP (fsinjP 1 0) => /=; by apply: (iffP andP)=> -[/fsfun_injective_inP ? /forallP ?]. Qed.
imports: HB(structures) mathcomp(ssreflect ssrbool ssrnat eqtype ssrfun seq) mathcomp(choice path finset finfun fintype bigop)