fact: Definition nHs (s : seq A) := \sum_(a in A) if N(a|s) == 0%nat then 0 else N(a|s) * log (size s / N(a|s)).
imports: mathcomp(all_ssreflect ssralg ssrnum) Reals mathcomp(Rstruct) ssrR realType_ext Reals_ext ssr_ext ssralg_ext logb fdist entropy convex ln_facts jensen num_occ