About the Authors
Michael Alekhnovich
University of California, San Diego

Mikhail (Misha) Alekhnovich was born on October 26, 1978 in Moscow, USSR and died on August 5, 2006 in a kayaking accident during a Class 6 whitewater expedition in Russia. From 1995 to 2000, he was a student in the Department of Mathematics and Mechanics at Moscow State University, where he was awarded Diploma with Honors. His diploma thesis, Pseudorandom generators in propositional proof complexity, was written under the supervision of Alexander A. Razborov. In 2000, he was a member in the special program on Computational Complexity at the Institute for Advanced Study in Princeton.

From 2001 to 2003, he was a graduate student in the Department of Mathematics of the Massachusetts Insitute of Technology. His doctoral thesis, written under the supervision of Madhu Sudan, is entitled Propositional Proof Systems: Efficiency and Automatizability. From 2003 to 2005 he held a postdoc position at the Institute for Advanced Study in Princeton, where his host was Avi Wigderson. From 2005 onwards, he was an assistant professor in the Department of Mathematics, University of California at San Diego.

Although only 27 years old at the time of his tragic death, Misha Alekhnovich already had an impressive string of research accomplishments to his credit, including major papers on propositional proof complexity, inapproximability, and computational learning theory.

His premature death has robbed the theory community of one of its brightest young stars.

This biographical sketch was written by Alasdair Urquhart and Toniann Pitassi. It is an adaptation of a longer obituary by A. Razborov, appearing in ACM SIGACT News 38/1 (March 2007), pp. 70-71. Misha's IAS home page will be maintained indefinitely.
Jan Johannsen
Institut für Informatik
Jan Johannsen obtained his doctoral degree from the University of Erlangen in 1996. After a two-year postdoc at UCSD he became an Emmy Noether junior research group leader at LMU Munich. Currently he teaches in the Computer Science Department of the LMU Munich and heads the departmental administration. His research interests are logic and computational complexity, in particular bounded arithmetic and propositional proof complexity, and their relation to the complexity of satisfiability.
Toniann Pitassi
University of Toronto
Toniann Pitassi studied chemistry and computer science as an undergraduate at Pennsylvania State University. After working for several years at Bell Laboratories, she pursued graduate work at the University of Toronto, with advisor Stephen Cook, receiving her Ph.D. in 1992. After a postdoc position at UCSD and faculty positions at the University of Pittsburgh and the University of Arizona, she returned to Toronto as a faculty member in 2000.
Alasdair Urquhart
University of Toronto
Alasdair Urquhart studied philosophy as an undergraduate in Edinburgh, Scotland, then did his undergraduate work at the University of Pittsburgh, where he received a Ph.D. in the Philosophy Department under the supervision of Nuel D. Belnap in 1973. Since 1970, he has been a faculty member in the Philosophy Department at the University of Toronto, where he is also cross-appointed in the Computer Science Department. His research interests include algebraic logic, non-classical logic, history of logic, and the complexity of propositional proofs.