One of the faults of the computer code that I'm writing these pages in
) is that it can't handle superscripts and
subscripts. That's one of the reasons I've relied so heavily on these
little embedded images with the math in them, which take so long to appear.
Well, I'm really going to be using a lot of subscripts in this
section, and I can't be embedding everything. So let's have the
convention that x_n will stand in for