theorem Th59:
  F is having_a_unity & F is associative & F is having_an_inverseOp implies
  F.((the_inverseOp_wrt F).d,d) = the_unity_wrt F &
    F.(d,(the_inverseOp_wrt F).d) = the_unity_wrt F
proof
  assume F is having_a_unity & F is associative & F is having_an_inverseOp;
  then the_inverseOp_wrt F is_an_inverseOp_wrt F by Def3;
  hence thesis;
end;
