Mathematics

Last time we began a discussion of the moduli space of D=4 N=2 vacua, and met several structures which we will now be revisiting in a two-pronged exposition, focusing on the one hand on the Hitchin system, and on the other on "counting instantons", i.e. localizing on an appropriately deformed moduli space, and reviewing some further properties thereof. It is precisely these exact results that allow one to test many recently proposed dualities.