Pi-stability on derived categories -- Tom Bridgeland, January 24, 2003

I explain the notion of a stability condition on a derived category T. This is an abstraction of Mike Douglas' notion of Pi-stability for D-Branes in string theory. The set Stab(T) of all stability conditions on a fixed category T is a complex manifold. I describe this space in the case when T is the derived category of a K3 surface.