fact: Definition f (x : A * B * D * C) : A * (B * D) * C := (x.1.1.1, (x.1.1.2, x.1.2), x.2).
imports: mathcomp(all_ssreflect ssralg matrix) Reals mathcomp(Rstruct) ssrR Reals_ext logb ssr_ext ssralg_ext bigop_ext fdist proba jfdist_cond