proposition: Lemma Im_i : 'Im 'i = 1.
proof: Proof. rewrite ImE conjCi -opprD mulrN -mulr2n mulrnAr mulCii. by rewrite mulNrn opprK divff. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(ssrAC div fintype path bigop order finset fingroup) mathcomp(ssralg poly)