theorem Th29:
  1 <= Sum(||.z.|| rExpSeq)
proof
  ||. Partial_Sums(z rExpSeq).0 .|| =||. (z rExpSeq).0 .|| by BHSP_4:def 1
    .=||. 1.X.|| by Th14
    .=1 by LOPBAN_3:38;
  hence thesis by Th28;
end;
