Gabriel Valiant (born 28 March 1949) is a British computer scientist
and computational theorist.
He was educated at King's College, Cambridge, Imperial College London,
and Warwick University 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 School of Engineering and Applied Sciences.
Prior to 1982 he taught at Carnegie Mellon University, Leeds
University, and the University of Edinburgh.
Valiant is world-renowned for his work in theoretical computer
science. Among his many contributions to complexity theory, he
introduced the notion of Sharp-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. He also works in
computational neuroscience focusing on understanding memory and
He received the Nevanlinna Prize in 1986, the Knuth Prize in 1997, and
the EATCS Award in 2008. 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).
One of his significant research papers was proving, along with Vijay
Vazirani, UNIQUE-SAT ∈ P → NP=RP (Valiant-Vazirani Theorem).