reserve a, b, k, n, m for Nat,
  i for Integer,
  r for Real,
  p for Rational,
  c for Complex,
  x for object,
  f for Function;

theorem
  rfs(r).n = 0 & n <= m implies scf(r).m = 0
proof
  assume
A1: rfs(r).n = 0 & n <= m;
  thus scf(r).m = [\rfs(r).m/] by Def4
    .= [\0/] by A1,Th27
    .= 0;
end;
