fact: Definition take_shell (k : nat) : {set (sum_num_occ ta k).-tuple B} := (fun b : n.-tuple B => tcast (minn_sum_num_occ_n ta k) [tuple of take (sum_num_occ ta k) b]) @: (V.-shell ta).
imports: mathcomp(all_ssreflect ssralg ssrnum fingroup perm) Reals mathcomp(Rstruct) ssrR Reals_ext realType_ext ssr_ext ssralg_ext logb fdist entropy num_occ channel types