TIME: 1:30 -- 2:30 pm, Tuesday, Feb 10, 2009 SPECIAL PLACE: Gates Commons (6th floor of CSE Building) SPEAKER: Yuval Peres, Microsoft Research TITLE: The Unreasonable Effectiveness of Martingales ABSTRACT: I will illustrate the effectiveness of Martingales and stopping times with four examples, involving waiting times for patterns in coin tossing, random graphs, mixing of random walks, and metric space embedding. A common theme is the way stopping time arguments often circumvent the wasteful "union bound" (bounding of the probability of a union by the sum of the individual probabilities).