fact: Definition c : `Ch(A, [finType of option A]) := fun a => FDist.make (f0 a) (f1 a).
imports: mathcomp(all_ssreflect all_algebra matrix) Reals mathcomp(mathcomp_extra Rstruct) ssrR Reals_ext realType_ext ssr_ext ssralg_ext logb fdist entropy binary_entropy_function channel hamming channel_code