proposition: Lemma dvdrNN a b : (- a %| - b) = (a %| b).
proof: Proof. by rewrite dvdNr dvdrN. Qed.
imports: HB(structures) Coq(ssreflect ssrfun ssrbool Arith.Wf_nat) mathcomp(eqtype ssrnat div seq path) mathcomp(ssralg fintype perm tuple choice generic_quotient) mathcomp(matrix bigop zmodp mxalgebra poly) stronglydiscrete