Gregory Chaitin

Gregory John Chaitin (/ˈtʃaɪtɪn/ CHY-tin; born 25 June 1947) is an Argentine-American mathematician and computer scientist. His work was foundational to the development of algorithmic information theory, and has been influential on metamathematics. He independently discovered what is today known as algorithmic (Kolmogorov or Solomonoff–Kolmogorov–Chaitin) complexity simultaneously with Andrei Kolmogorov and Ray Solomonoff. Gregory Chaitin is Jewish. He attended the Bronx High School of Science and the City College of New York, where he (still in his teens) developed the theory that led to his independent discovery of algorithmic complexity. In 1975, Chaitin defined Chaitin's constant Ω, a real number whose digits are equidistributed and which is sometimes informally described as an expression of the probability that a random program will halt. Ω has the mathematical property that it is definable, with asymptotic approximations from below (but not from above), but not computable. Chaitin is also the originator of using graph coloring to do register allocation in compiling, a process known as Chaitin's algorithm. He was formerly a researcher at IBM's Thomas J. Watson Research Center in New York, where he wrote more than 10 books that have been translated into about 15 languages. Afterwards Chaitin became interested in questions of metabiology and information-theoretic formalizations of the theory of evolution, and he was one of the founding members of the Institute for Advanced Studies at Mohammed VI Polytechnic University in Morocco.