
theorem Th6:
  for R being non empty RelStr,
      X being Subset of R
  for x being object st x in LAp X holds
    Class (the InternalRel of R, x) c= X
proof
  let R be non empty RelStr,
      X be Subset of R;
  let x be object;
  assume x in LAp X; then
  ex x1 being Element of R st x = x1 &
  Class (the InternalRel of R, x1) c= X;
  hence thesis;
end;
