Leslie Gabriel ValiantFRS[4][5] (born 28 March 1949) is a British American[6] computer scientist and computational theorist.[7][8] He was born to a chemical engineer father and a translator mother.[9] He is currently the T. Jefferson Coolidge Professor of Computer Science and Applied Mathematics at Harvard University.[10][11][12][13] Valiant was awarded the Turing Award in 2010, having been described by the A.C.M. as a heroic figure in theoretical computer science and a role model for his courage and creativity in addressing some of the deepest unsolved problems in science; in particular for his "striking combination of depth and breadth".[6]
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 ("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. In computer systems, he is most well-known for introducing the bulk synchronous parallel processing model. 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.
Valiant's 2013 book is Probably Approximately Correct: Nature's Algorithms for Learning and Prospering in a Complex World.[16] In it he argues, among other things, that evolutionary biology does not explain the rate at which evolution occurs, writing, for example, "The evidence for Darwin's general schema for evolution being essentially correct is convincing to the great majority of biologists. This author has been to enough natural history museums to be convinced himself. All this, however, does not mean the current theory of evolution is adequately explanatory. At present the theory of evolution can offer no account of the rate at which evolution progresses to develop complex mechanisms or to maintain them in changing environments."
Valiant has contributed in a decisive way to the growth of almost every branch of theoretical computer science. His work is concerned mainly with quantifying mathematically the resource costs of solving problems on a computer. In early work (1975) he found the asymptotically fastest algorithm known for recognising context-free languages. At the same time, he pioneered the use of communication properties of graphs for analysing computations. In 1977 he defined the notion of #P-completeness ("sharp-P") and established its utility in classifying counting or enumeration problems according to computational tractability. The first application was to counting matchings (the matrix permanent function). In 1984 Valiant introduced a definition of inductive learning that for the first time reconciles computational feasibility with the applicability to non-trivial classes of logical rules to be learned.* More recently he has devised a scheme for efficient routing of communications in a multiprocessor system. He showed that the overheads involved even in a sparse network need not grow with the size of the system. This establishes, from a theoretical viewpoint, the possibility of efficient general purpose parallel computers.[5]
The citation for his A.M. Turing Award reads:
For transformative contributions to the theory of computation, including the theory of probably approximately correct (PAC) learning, the complexity of enumeration and of algebraic computation, and the theory of parallel and distributed computing.[6]
Personal life
His two sons Gregory Valiant[22] and Paul Valiant[23] are both also theoretical computer scientists.[8]
References
^Valiant, L.; Vazirani, V. (1986). "NP is as easy as detecting unique solutions" (PDF). Theoretical Computer Science. 47: 85–93. doi:10.1016/0304-3975(86)90135-0.
^Valiant, L. G. (1979). "The Complexity of Enumeration and Reliability Problems". SIAM Journal on Computing. 8 (3): 410–421. doi:10.1137/0208032.
^ abcde"Leslie G. Valiant - A.M. Turing Award Laureate". A.M. Turing Award. Retrieved 9 January 2019.
^Hoffmann, L. (2011). "Q&A: Leslie Valiant discusses machine learning, parallel computing, and computational neuroscience". Communications of the ACM. 54 (6): 128. doi:10.1145/1953122.1953152.
^ abAnon (2017). "Valiant, Prof. Leslie Gabriel". Who's Who. ukwhoswho.com (online Oxford University Press ed.). A & C Black, an imprint of Bloomsbury Publishing plc. doi:10.1093/ww/9780199540884.013.U40928. (Subscription or UK public library membership required.)(subscription required)
^"A. M. Turing Award Oral History Interview with Leslie Gabriel Valiant" (PDF).
^Leslie Valiant author profile page at the ACM Digital Library
^Wigderson, A. (2009). "The work of Leslie Valiant". Proceedings of the 41st annual ACM symposium on Symposium on theory of computing - STOC '09. pp. 1–2. doi:10.1145/1536414.1536415. ISBN9781605585062. S2CID 15370663.
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January 27, 2023
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Les Valiant redirects here Not to be confused with Valiant disambiguation Leslie Gabriel Valiant FRS 4 5 born 28 March 1949 is a British American 6 computer scientist and computational theorist 7 8 He was born to a chemical engineer father and a translator mother 9 He is currently the T Jefferson Coolidge Professor of Computer Science and Applied Mathematics at Harvard University 10 11 12 13 Valiant was awarded the Turing Award in 2010 having been described by the A C M as a heroic figure in theoretical computer science and a role model for his courage and creativity in addressing some of the deepest unsolved problems in science in particular for his striking combination of depth and breadth 6 Leslie ValiantFRSValiant in 2012BornLeslie Gabriel Valiant 1949 03 28 28 March 1949 age 73 Budapest Hungarian RepublicNationalityBritishAlma materUniversity of Cambridge BA Imperial College London MS University of Warwick PhD Known forValiant Vazirani theorem 1 Counting problem 2 Probably approximately correct learningAwardsTuring Award 2010 EATCS Award 2008 Member of the National Academy of Sciences 2001 Knuth Prize 1997 AAAI Fellow 1992 Nevanlinna Prize 1986 Scientific careerFieldsMathematicsTheoretical computer scienceComputational learning theory Theoretical neuroscienceInstitutionsHarvard University University of EdinburghThesisDecision Procedures for Families of Deterministic Pushdown Automata 1974 Doctoral advisorMike Paterson 3 Doctoral studentsMark Jerrum Michael Kearns Dan Roth 3 Websitepeople wbr seas wbr harvard wbr edu wbr valiant Contents 1 Education 2 Research and career 2 1 Awards and honors 3 Personal life 4 References 5 External linksEducation EditValiant was educated at King s College Cambridge 14 6 Imperial College London 14 6 and the University of Warwick where he received a PhD in computer science in 1974 15 3 Research and career EditValiant is world renowned for his work in theoretical computer science Among his many contributions to complexity theory he introduced the notion of P completeness 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 In computer systems he is most well known for introducing the bulk synchronous parallel processing model 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 Valiant s 2013 book is Probably Approximately Correct Nature s Algorithms for Learning and Prospering in a Complex World 16 In it he argues among other things that evolutionary biology does not explain the rate at which evolution occurs writing for example The evidence for Darwin s general schema for evolution being essentially correct is convincing to the great majority of biologists This author has been to enough natural history museums to be convinced himself All this however does not mean the current theory of evolution is adequately explanatory At present the theory of evolution can offer no account of the rate at which evolution progresses to develop complex mechanisms or to maintain them in changing environments Valiant 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 the University of Leeds and the University of Edinburgh Awards and honors Edit Valiant received the Nevanlinna Prize in 1986 the Knuth Prize in 1997 the EATCS Award in 2008 17 and the Turing Award in 2010 18 19 He was elected a Fellow of the Royal Society FRS in 1991 4 a Fellow of the Association for the Advancement of Artificial Intelligence AAAI in 1992 20 and a member of the United States National Academy of Sciences in 2001 21 Valiant s nomination for the Royal Society reads Valiant has contributed in a decisive way to the growth of almost every branch of theoretical computer science His work is concerned mainly with quantifying mathematically the resource costs of solving problems on a computer In early work 1975 he found the asymptotically fastest algorithm known for recognising context free languages At the same time he pioneered the use of communication properties of graphs for analysing computations In 1977 he defined the notion of P completeness sharp P and established its utility in classifying counting or enumeration problems according to computational tractability The first application was to counting matchings the matrix permanent function In 1984 Valiant introduced a definition of inductive learning that for the first time reconciles computational feasibility with the applicability to non trivial classes of logical rules to be learned More recently he has devised a scheme for efficient routing of communications in a multiprocessor system He showed that the overheads involved even in a sparse network need not grow with the size of the system This establishes from a theoretical viewpoint the possibility of efficient general purpose parallel computers 5 The citation for his A M Turing Award reads For transformative contributions to the theory of computation including the theory of probably approximately correct PAC learning the complexity of enumeration and of algebraic computation and the theory of parallel and distributed computing 6 Personal life EditHis two sons Gregory Valiant 22 and Paul Valiant 23 are both also theoretical computer scientists 8 References Edit Valiant L Vazirani V 1986 NP is as easy as detecting unique solutions PDF Theoretical Computer Science 47 85 93 doi 10 1016 0304 3975 86 90135 0 Valiant L G 1979 The Complexity of Enumeration and Reliability Problems SIAM Journal on Computing 8 3 410 421 doi 10 1137 0208032 a b c Leslie Valiant at the Mathematics Genealogy Project a b Leslie Valiant FRS London Royal Society 1991 a b DServe Archive Catalog Show a b c d e Leslie G Valiant A M Turing Award Laureate A M Turing Award Retrieved 9 January 2019 Hoffmann L 2011 Q amp A Leslie Valiant discusses machine learning parallel computing and computational neuroscience Communications of the ACM 54 6 128 doi 10 1145 1953122 1953152 a b Anon 2017 Valiant Prof Leslie Gabriel Who s Who ukwhoswho com online Oxford University Press ed A amp C Black an imprint of Bloomsbury Publishing plc doi 10 1093 ww 9780199540884 013 U40928 Subscription or UK public library membership required subscription required A M Turing Award Oral History Interview with Leslie Gabriel Valiant PDF Leslie Valiant author profile page at the ACM Digital Library Wigderson A 2009 The work of Leslie Valiant Proceedings of the 41st annual ACM symposium on Symposium on theory of computing STOC 09 pp 1 2 doi 10 1145 1536414 1536415 ISBN 9781605585062 S2CID 15370663 Leslie G Valiant at DBLP Bibliography Server Valiant Leslie 1984 A theory of the learnable PDF Communications of the ACM 27 11 1134 1142 doi 10 1145 1968 1972 S2CID 12837541 a b CV of Leslie G Valiant PDF Harvard University Retrieved 9 January 2019 Valiant Leslie 1973 Decision procedures for families of deterministic pushdown automata warwick ac uk PhD thesis University of Warwick OCLC 726087468 EThOS uk bl ethos 475930 Basic Books ISBN 9780465032716 David Peleg The EATCS Award 2008 Laudatio for Professor Leslie Valiant European Association of Theoretical Computer Science Josh Fishman Probably Approximately Correct Inventor From Harvard U Wins Turing Award Chronicle of Higher Education 9 March 2011 ACM Turing Award Goes to Innovator in Machine Learning ACM Computing News Elected AAAI Fellows Association for the Advancement of Artificial Intelligence Member Directory Leslie G Valiant National Academy of Sciences Gregory Valiant Homepage Paul Valiant s homepageExternal links Edit This article incorporates text available under the CC BY 4 0 license Retrieved from https en wikipedia org w index php title Leslie Valiant amp oldid 1125114813, wikipedia, wiki, book, books, library,
