Dear Mike,

you're right of course that a Best algorithm can to some extent emulate Progressive Revelation as I described it, but I think a fully worked-out PR model would go further. Also, of course, it's silly to work from a fully populated rectangular matrix if there's no intention of using all of it. Better perhaps to use a data model that has a "matrix" representation or equivalent at its core for the global data and a cloud of "data bits" for the non-global stuff.

Cheers - k