reserve c, c1, c2, d, d1, d2, e, y for Real,
  k, n, m, N, n1, N0, N1, N2, N3, M for Element of NAT,
  x for set;

theorem
  for f,g being Real_Sequence, M being Element of NAT holds for N st N
  >= M+1 holds (for n st M+1 <= n & n <= N holds f.n <= g.n) implies Sum(f,N,M)
  <= Sum (g,N,M) by Lm16;
