Seminar

http://events.berkeley.edu/index.php/calendar/sn/math.html?event_ID=116887

Most invariants of a symplectic manifold derive in some way from a count of J-holomorphic curves. However, in a general symplectic manifold one often cannot count curves directly in a robust way, i.e. so that the count is independent of the choice of perturbation. Instead one has to define a virtual count. This talk will try to give an elementary description of the problem and will describe some recent approaches to it.