fact: Definition alpha_fun (m0 : 'I_m) (n0 : 'I_n) (beta : 'M[R]_(m, n) * 'M[R]_(m, n)) (x : 'F_2) : R := \sum_(t = \row_(i < n) (0 : 'F_2) [~'V m0 :\ n0]) ((\delta ('V m0) t)%:R * \prod_(n1 in 'V m0 :\ n0) if t ``_ n1 == Zp0 then beta.1 m0 n1 else beta.2 m0 n1)%R.
imports: mathcomp(all_ssreflect ssralg fingroup finalg perm zmodp) mathcomp(matrix vector ssrnum) Reals Lra mathcomp(Rstruct) ssrR Reals_ext realType_ext ssr_ext ssralg_ext num_occ bigop_ext fdist channel pproba f2 linearcode subgraph_partition tanner tanner_partition hamming binary_symmetric_channel decoding channel_code summary checksum summary_tanner