fact: Definition perm_ids (i : 'I_n) := match fintype.split (ord_split i) with | inl j => nth 0 idsA j | inr j => proj1_sig (ids1 j) end.
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