proposition: Theorem build_tree_ok : forall k i, tanner_rel H =2 graph (build_tree H rW (k:=k) i).
proof: Proof. rewrite /build_tree. move=> k i a b. case Htan: (tanner_rel H a b). symmetry. apply build_tree_rec_ok with (s:=[::]). + by rewrite card_sum !card_ord card0 subn0. + by []. + exact: build_tree_full. + exact: build_tree_full. + by []. symmetry. move: Htan. exact/contraFF/build_tree_rec_sound. Qed.
imports: Wf_nat Init.Wf Recdef Reals mathcomp(all_ssreflect perm zmodp matrix ssralg) mathcomp(Rstruct) ssrR Reals_ext ssr_ext ssralg_ext bigop_ext f2 fdist channel pproba linearcode subgraph_partition tanner tanner_partition summary ldpc checksum ldpc_algo