proposition: Lemma Crect x : x = 'Re x + 'i * 'Im x.
proof: Proof. rewrite !(ReE, ImE) 2!mulrA mulCii mulN1r opprB -mulrDl. by rewrite addrACA subrr addr0 mulrDl -splitr. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(ssrAC div fintype path bigop order finset fingroup) mathcomp(ssralg poly)