proposition: Lemma eqCmodN e x y : (- x == y %[mod e])%C = (x == - y %[mod e])%C.
proof: Proof. by rewrite eqCmod_sym /eqCmod !opprK addrC. 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)