Hello Conrad! GREAT, now you get it!! And you are correct, asymetrical would be a better term. This was a fleeting thought, I did not burn many ergs on it. My only point was that it addresses one of the drawbacks of AIM; averaging down to zero. If you would like to discuss this offline, let me know. Regards, Leap P.S. I have not been able to locate the english version of your book.