fact: Definition HL_maximal f (x : R) : \bar R := ereal_sup [set iavg f (ball x r) | r in `]0, +oo[%classic%R].
imports: HB(structures) mathcomp(all_ssreflect ssralg ssrnum ssrint interval finmap) mathcomp(mathcomp_extra boolp classical_sets functions) mathcomp(cardinality fsbigop ) signed reals ereal topology normedtype sequences real_interval esum measure lebesgue_measure numfun