theorem Th29:
  for W1,W2 being strict Submodule of V holds the carrier of W1 =
  the carrier of W2 implies W1 = W2
proof
  let W1,W2 be strict Submodule of V;
  assume the carrier of W1 = the carrier of W2;
  then W1 is Submodule of W2 & W2 is Submodule of W1 by Th27;
  hence thesis by Th25;
end;
