What mathematics says about what computers can and cannot do


Stephen A. Cook


Department of Computer Science University of Toronto


Thursday, 3 January 2013, 17:00 to 18:00


  • Homi Bhabha Auditorium


The security of computer encryption protocols such as for credit card transactions depends on unproven mathematical assumptions concerning the limits of computation. The central assumption is the conjecture known as 'P not equal NP' (one of the million dollar questions listed by the Clay Mathematics Institute). I will explain the conjecture, its background and importance, and related issues from the field of computational complexity.


About the speaker:

Stephen A. Cook was born in Buffalo, New York, received his BSc degree from University of Michigan in 1961, and his S.M. and PhD degrees from Harvard University in 1962 and 1966 respectively. From 1966 to 1970 he was Assistant Professor, University of California, Berkeley. He joined the faculty at the University of Toronto in 1970 as an Associate Professor, and was promoted to Professor in 1975 and University Professor in 1985. His principal research areas are computational complexity and proof complexity, with excursions into programming language semantics and parallel computation. He is author of many research papers, including his famous 1971 paper "The Complexity of Theorem Proving Procedures" which introduced the theory of NP completeness and proved that the Boolean satisfiability problem is NP complete. He is the 1982 recipient of the Turing award. He was awarded a Steacie Fellowship in 1977,a Killam Research Fellowship in 1982, and received the CRM/Fields Institute Prize in 1999. He is a fellow of the Royal Society of London, Royal Society of Canada, and was elected to membership in the National Academy of Sciences (United States) and the American Academy of Arts and Sciences. Thirty students have completed their PhD degrees under his supervision.

[Photograph by Kevin Van Paassen/The Globe and Mail]