theorem Th28:
  n>=1 implies dseq.n<=Sum(eseq)
proof
  assume
A1: n>=1;
  then for k holds 0<=cseq(n).k & cseq(n).k<=eseq.k by Th14;
  then Sum(cseq(n))<=Sum(eseq) by Th23,SERIES_1:20;
  hence thesis by A1,Th21;
end;
