theorem Th2:
  z|^12 = z*z*z*z*z*z*z*z*z*z*z*z
  proof
A1: 12 = 11+1;
    z|^11 = z*z*z*z*z*z*z*z*z*z*z by Th1;
    hence thesis by A1,NEWTON:6;
  end;
