CM uses nearly identical "bowls" for the bottom of the italic u and v; this contributes to a pleasing smoothness to the page layout, but the two letters are very similar. Zapf designed fonts in which the two letters contrast more. The u might have a straight lefthand side, and the v could be more rounded, or the u might be rounded, but the v would be angular. For calligraphy, I quite like the sharp angle at the bottom of a v, but when writing by hand, there are many opportunities to ameliorate the jarring angle with other visual aspects of the page layout. With typography, you have to choose the trade-offs once and for all. No matter what font you are using for math, I think it would be a good idea to avoid mixing u and v closely. There are so many other good pairings to choose from. Hilarie