
theorem Th22:
  for L being non empty RelStr, N being non empty NetStr over L
for x being Element of L, y being set holds y is Element of N iff y is Element
  of x "/\" N
proof
  let L be non empty RelStr, N be non empty NetStr over L, x be Element of L,
  y be set;
  the RelStr of x "/\" N = the RelStr of N by Def3;
  hence thesis;
end;
