fact: Definition eseries : (\bar R)^nat := [sequence \sum_(0 <= k < n) u_ k]_n.
imports: mathcomp(all_ssreflect ssralg ssrint ssrnum matrix) mathcomp(interval rat) mathcomp(mathcomp_extra boolp classical_sets functions) mathcomp(set_interval) reals ereal signed topology normedtype landau