proposition: Lemma eqCmod_sym e x y : ((x == y %[mod e]) = (y == x %[mod e]))%C.
proof: Proof. by rewrite /eqCmod -opprB rpredN. 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)