proposition: Lemma card_unit_cols : #|unit_cols| = m.
proof: Proof. by rewrite /unit_cols cols_1 card_imset; [apply card_ord | apply cols_1_inj]. Qed.
imports: mathcomp(all_ssreflect ssralg fingroup finalg perm zmodp) mathcomp(matrix mxalgebra vector) mathcomp(Rstruct) realType_ext ssr_ext ssralg_ext f2 linearcode natbin ssrR hamming bigop_ext fdist proba channel channel_code decoding binary_symmetric_channel