fact: Definition ndseq_closed := forall F, nondecreasing_seq F -> (forall i, G (F i)) -> G (\bigcup_i (F i)).
imports: mathcomp(all_ssreflect all_algebra finmap) mathcomp(mathcomp_extra boolp classical_sets functions) mathcomp(cardinality fsbigop ) reals ereal signed topology normedtype sequences esum numfun HB(structures)