theorem
  x is being_an_amalgam_of_squares & y is generated_from_squares implies
  x*y is generated_from_squares
proof
  assume that
A1: x is being_an_amalgam_of_squares and
A2: y is generated_from_squares;
  x is generated_from_squares by A1,Lm40;
  hence thesis by A2,Lm87;
end;
