fact: Definition fdist_of_ffun (A : finType) n (f : {ffun A -> 'I_n.+2}) (Hf : (\sum_(a in A) f a)%nat == n.+1) : {fdist A}.
imports: mathcomp(all_ssreflect ssralg ssrnum perm) mathcomp(matrix) mathcomp(Rstruct) Reals ssrR Reals_ext realType_ext ssr_ext ssralg_ext logb fdist proba entropy num_occ channel_code channel typ_seq