proposition: Lemma eqCmod_transr e x y z : (x == y %[mod e])%C -> (z == x %[mod e])%C = (z == y %[mod e])%C.
proof: Proof. by move/(sym_right_transitive (eqCmod_sym e) (@eqCmod_trans e)). 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)