1. Anderson School of Management, University of California, Los Angeles, California 90024;
2. Departments of Computer Science, Electrical and Computer Engineering, Statistical Science, Mathematics, and Biostatistics & Bioinformatics, Duke University, Durham, North Carolina 27708;
3. Simon Business School, University of Rochester, Rochester, New York 14627;
4. Department of Mathematics, William & Mary, Williamsburg, Virginia 23185