
theorem Th7:
  for L being non empty 1-sorted, N being non empty NetStr over L,
f being Function of N,N holds N * f = NetStr(#the carrier of N,the InternalRel
    of N,(the mapping of N)*f#)
proof
  let L be non empty 1-sorted, N be non empty NetStr over L, f be Function of
  N,N;
  the RelStr of N*f=the RelStr of N by Def2;
  hence thesis by Def2;
end;
