Daniel Ullman

Dan Ullman
Professor of Mathematics
Phillips Hall
801 22nd St. NW
Washington, District Of Columbia 20052
[email protected]
Dan's Website

Areas of Expertise

  • Chromatic Theory of graphs
  • Combinatorial Game Theory
  • Theory of Fractional Graph Invariants
  • Mathematics and Politics

Daniel Ullman currently serves as a Professor of Mathematics.  He is the Director of the William Lowell Putnam Mathematical Competition, the pre-eminent college mathematics contest.  He also serves as the Problems Editor of the American Mathematical Monthly.  He served as Associate Dean for Undergraduate Studies in the Columbian College of Arts and Sciences at GW from 2011 to 2015 and also as the American Mathematical Society Congressional Fellow from 2006 to 2007.  He was D.C. Director of the 2001 International Mathematical Olympiad, and Deputy Leader of the U.S. delegation to the International Mathematical Olympiad in 1991 in Stockholm and 1992 in Moscow. From 2007 to 2010, Ullman directed the D.C. Math Circle, a mathematics enrichment program for 8th-grade D.C. math students.

Current Research

  • Graph Theory
  • Combinatorics


  • A.B. 1979, Harvard University
  • Ph.D. 1985, University of California, Berkeley


  • On tensor powers of integer programs, SIAM J. Disc. Math. 5 (1992) 127-143 (with R. Pemantle, J. Propp).
  • Sequential compounds of combinatorial games, J. Theor. Comp. Sci. 119, (1993) 311-321 (with W. Stromquist).
  • Fractional isomorphism of graphs, J. Graph Theory 132 (1994) 247-265 (with M. Ramana, E. Scheinerman).
  • The fractional chromatic number of Mycielski's graphs, J. Graph Theory 19 (1995) 411-416 (with J. Propp, M. Larsen).
  • On point-hyperspace graphs, J. Graph Theory 20 (1995) 19-35 (with E. Scheinerman, A. Trenk).
  • The Mathematics of Politics, second edition (with E. A. Robinson), CRC Press, 2017.
  • Fractional Graph Theory (with E. A. Scheinerman), Wiley, 1997; reprinted by Dover, 2011