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Joseph Yehuda Halpern

  • Joseph Yehuda Halpern
  • Dept: Computer Science
  • Title: Professor
  • Address: 412 Gates Hall
  • Phone: 607 255-9562
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Joseph Y. Halpern received a B.Sc. in mathematics from the University of Toronto in 1975 and a Ph.D. in mathematics
from Harvard in 1981.  In between, he spent two years as the head of the Mathematics Department at Bawku Secondary School, in Ghana. After a year as a visiting scientist at MIT, he joined the IBM Almaden Research Center in 1982, where he remained until 1996, also serving as a consulting professor at Stanford.  In 1996, he moved to Cornell University, where he is a professor in Computer Science, and was department department chair 2010-14.

Halpern's major research interests are in reasoning about knowledge and uncertainty, qualitative reasoning, causality, belief revision, (fault-tolerant) distributed computation, game theory, decision theory, and security.  Together with his former student, Yoram Moses, he pioneered  the approach of applying reasoning about knowledge to analyzing distributed
protocols and multi-agent systems.  He has coauthored 5 patents, two books ("Reasoning About Knowledge" and "Reasoning about Uncertainty"), and over 300 technical publications.

Halpern is a Fellow of the AAAI, the ACM, and the AAAS. Among other awards, he received the ACM SIGART Autonomous Agents Research Award in 2011 , the Dijkstra Prize in 2009, the ACM/AAAI Newell Award in 2008, the Godel Prize in 1997, was a Guggenheim Fellow in 2001 -02, and a Fulbright Fellow in 2001-02 and 2009-10.  Two of his papers hav e won best-paper prizes at IJCAI (1985 and 1991 ), and another two won one at the Knowledge Representation and Reasoning Conference (2006 and 2012). He was editor-in-chief of the Journal of the
ACM (1997 -2003) and has been program chair of a number of conferences, including the Symposium on Theory in Computing (STOC), Logic in Computer Science (LICS), Uncertainty in AI (UAI), Principles of Distributed Computing (PODC), and Theoretical Aspects of Rationality and Knowledge (TARK).

Selected Publications

  • Halpern, Joseph Yehuda, R. Pass. 2014. "Algorithmic rationality: game theory with costly computation." Journal of Economic Theory.
  • Halpern, Joseph Yehuda. 2008. "Beyond Nash equilibrium: solution concepts for the 21st century." Paper presented at Proceedings of Twenty-Seventh Annual ACM Symposium on Principles of Distributed Computing
  • Halpern, Joseph Yehuda, J. Pearl. 2005. "Causes and explanations: A structural-model approach. Part I: Causes." British Journal for the Philosophy of Science 56 (4): 843-887.
  • Halpern, Joseph Yehuda. 2003. Reasoning About Uncertainty. MIT Press.
  • Fagin, R., Joseph Yehuda Halpern, Y. Moses, M.Y. Vardi. 1995. Reasoning About Knowledge. MIT Press.

Selected Awards and Honors

  • IEEE Fellow (IEEE) 2012
  • Economic Theory Fellow (Society for the Advancement of Economic Theory) 2011
  • ACM/SIGART Autonomous Agents Research Award, (ACM/SIGART) 2011
  • ACM/AAAI Newell Award 2009
  • Fellow of AAAS (AAAS) 2005



  • BS (Mathematics), University of Toronto, 1975
  • MS (Mathematics), Harvard University, 1979
  • Ph D (Mathematics), Harvard University, 1981