Leonid Levin

Leonid Anatolievich Levin ( ; ; ; born November 2, 1948) is a Soviet-American mathematician and computer scientist.

He is known for his work in randomness in computing, algorithmic complexity and intractability, average-case complexity, After researching algorithmic problems of information theory at the Moscow Institute of Information Transmission of the National Academy of Sciences in 1972–1973, and a position as senior research scientist at the Moscow National Research Institute of Integrated Automation for the Oil/Gas Industry in 1973–1977, he emigrated to the U.S. in 1978 and also earned a Ph.D. at the Massachusetts Institute of Technology (MIT) in 1979. foundations of mathematics and computer science, algorithmic probability, theory of computation, and information theory.

His life is described in a chapter of the book Out of Their Minds: The Lives and Discoveries of 15 Great Computer Scientists.

Levin and Stephen Cook independently discovered the existence of NP-complete problems. This NP-completeness theorem, often called the Cook–Levin theorem, was a basis for one of the seven Millennium Prize Problems declared by the Clay Mathematics Institute with a $1,000,000 prize offered. The Cook–Levin theorem was a breakthrough in computer science and an important step in the development of the theory of computational complexity. Levin's journal article on this theorem was published in 1973; he had lectured on the ideas in it for some years before that time (see Trakhtenbrot's survey), though complete formal writing of the results took place after Cook's publication.

Levin was awarded the Knuth Prize in 2012 for his discovery of NP-completeness and the development of average-case complexity.

He is currently a professor of computer science at Boston University, where he began teaching in 1980.