Leslie Valiant

Leslie Valiant bigraphy, stories - British computer scientist

Leslie Valiant : biography

28 March 1949 –

Leslie Gabriel Valiant FRS (born 28 March 1949) is a British computer scientist and computational theorist.

Valiant is world-renowned for his work in theoretical computer science. Among his many contributions to complexity theory, he introduced the notion of #P-completeness to explain why enumeration and reliability problems are intractable. He also introduced the "probably approximately correct" (PAC) model of machine learning that has helped the field of computational learning theory grow, and the concept of holographic algorithms. His earlier work in automata theory includes an algorithm for context-free parsing, which is (as of 2010) still the asymptotically fastest known. He also works in computational neuroscience focusing on understanding memory and learning.

Together with Vijay Vazirani, Valiant proved the Valiant–Vazirani theorem.


He was educated at King’s College, Cambridge, Imperial College London, and University of Warwick where he received his Ph.D. in computer science in 1974. He started teaching at Harvard University in 1982 and is currently the T. Jefferson Coolidge Professor of Computer Science and Applied Mathematics in the Harvard School of Engineering and Applied Sciences. Prior to 1982 he taught at Carnegie Mellon University, Leeds University, and the University of Edinburgh.


He received the Nevanlinna Prize in 1986, the Knuth Prize in 1997, the EATCS Award in 2008,David Peleg [https://www.eatcs.org/index.php/eatcs-award/625 The EATCS Award 2008 – Laudatio for Professor Leslie Valiant] European Association of Theoretical Computer Science. and the ACM Turing Award in 2010.Josh Fishman Chronicle of Higher Education March 9, 2011. ACM Computing News He is a Fellow of the Royal Society (London), a Fellow of the American Association for Artificial Intelligence, and a member of the National Academy of Sciences (USA).