fact: Definition idsA := [seq i <- enum 'I_n | col i (Hamming.PCM m) \in non_unit_cols].
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