Um, I think I'm inventing my own notation.  By "so that A + B ~ B" ,   I 
meant "would the speed improvement from adding J5 and Strongtalk-types 
to Squeak, be approximately equal to the speed improvement from just 
adding J5 to Squeak".

>   Let's call the speed gains from typing a la StrongTalk, A, and let's 
> call the speed gains from J5, B.
>
> Would J5 and  types together equal a speed improvement of A + B? 
> Or does the stuff Ian is doing with J5 involve some kind of magic 
> typing behind-the-scenes, so that A + B ~ B? 
>
>