fact: Record receivable := mkReceivable { receivable_rV :> 'rV[B]_n ; receivableP : receivable_prop receivable_rV }.
imports: mathcomp(all_ssreflect all_algebra zmodp matrix) Reals mathcomp(Rstruct) ssrR Reals_ext ssr_ext ssralg_ext bigop_ext fdist proba channel jfdist_cond