sentences:  In 2000 he greatly expanded Ramanujan's theory of partition congruences, and in work with Kathrin Bringmann he has made important contributions to the theory of Maass forms, functions which include Ramanujan's mock theta functions as examples.In 2007 Don Zagier gave a Seminar Bourbaki address on the work of Bringmann, Ono, and Zwegers on the mock theta functions.The 2009 SASTRA Ramanujan Prize, awarded to a young mathematician under the age of 32, was awarded to Kathrin Bringmann for this joint work with Ono.