Now that I'm not rushing to post this, I'm pretty sure it should be S(t) = T_[4t](S({4t}) (but at this point I can no longer trust anything I say). I wrote: << S({4t}) = T_[4t](S(t)) ________________________________________________________________________________________ "Outside of a dog, a book is man's best friend. Inside of a dog, it's too dark to read." --Groucho Marx