fact: Definition pre_op (X : neset {necset A}) : {convex_set A} := CSet.Pack (CSet.Mixin (hull_is_convex (\bigcup_(i in X) idfun i)%:ne)).
imports: HB(structures) Reals mathcomp(all_ssreflect ssralg ssrnum) mathcomp(mathcomp_extra boolp classical_sets Rstruct reals) mathcomp(finmap) Reals_ext realType_ext classical_sets_ext ssrR fdist fsdist convex