proposition: Lemma modz_abs m d : (m %% `|d|%N)%Z = (m %% d)%Z.
proof: Proof. by rewrite {2}[d]intEsign mulr_sign; case: ifP; rewrite ?modzN. Qed.
imports: HB(structures) mathcomp(ssreflect ssrbool ssrfun eqtype ssrnat seq path) mathcomp(div choice fintype tuple finfun bigop prime order) mathcomp(ssralg poly ssrnum ssrint archimedean rat matrix) mathcomp(polydiv perm zmodp mxalgebra vector)