proposition: Lemma algC_autK nu : cancel nu (algC_invaut nu).
proof: Proof. exact: inj_can_sym (algC_invautK nu) (fmorph_inj nu). Qed.
imports: HB(structures) mathcomp(ssreflect ssrbool ssrfun ssrnat eqtype seq choice) mathcomp(div fintype path bigop finset prime order ssralg) mathcomp(poly polydiv mxpoly generic_quotient countalg) mathcomp(ssrnum closed_field ssrint archimedean rat intdiv) mathcomp(algebraics_fundamentals)