proposition: Lemma dest_dist_ge0 a : dest_dist a >= 0.
proof: Proof. rewrite /dest_dist; case: ifP => // _. by rewrite mulr_ge0 // ?DegreeDistribution.p0 // invr_ge0 ler0n. Qed.
imports: mathcomp(all_ssreflect ssralg fingroup zmodp poly ssrnum) mathcomp(matrix perm) ssr_ext ssralg_ext fdist subgraph_partition tanner