There will be an active program of research activities, seminars and workshops throughout the September 10 - December 14, 2012 period and core participants will be in residence at IPAM continuously for these fourteen weeks. The program will open with tutorials, and will be punctuated by four major workshops and a culminating workshop at UCLA’s Lake Arrowhead Conference Center. Several distinguished senior researchers will be in residence for the entire period. Between the workshops there will be a program of activities involving the long-term and short-term participants, as well as visitors.