- Church, Alonzo
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born June 14, 1903, Washington, D.C., U.S.died Aug. 11, 1995, Hudson, OhioU.S. mathematician.He earned a Ph.D. from Princeton University. His contributions to number theory and the theories of algorithms and computability laid the foundations of computer science. The rule known as Church's theorem or Church's thesis (proposed independently by Alan M. Turing) states that only recursive functions can be calculated mechanically and implies that arithmetic procedures cannot be used to decide the consistency of statements formulated in accordance with the laws of arithmetic. He wrote the standard textbook Introduction to Mathematical Logic (1956) and helped found the Journal of Symbolic Logic, which he edited until 1979.
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▪ 1996U.S. mathematician (b. June 14, 1903, Washington, D.C.—d. Aug. 11, 1995, Hudson, Ohio), was a pioneer in the field of mathematical logic. His contributions to number theory and the theories of algorithms and computability laid the theoretical foundations of computer science. Church was educated at Princeton University (A.B., 1924; Ph.D., 1927) and spent a year as a fellow at Harvard University and a year at the University of Göttingen, Germany, before returning to his alma mater to teach (1929-67) mathematics and philosophy. Just before reaching retirement age at Princeton, he took (1967-90) a professorship at the University of California, Los Angeles. In 61 years of teaching, he supervised 31 doctoral students, including such notable mathematicians as Alan M. Turing, Stephen Cole Kleene, John G. Kemeny, Raymond M. Smullyan, and Martin Davis. Many of Church's innovations originated in the 1930s, such as his creation of λ (lambda) calculus, which later became an important tool for computer scientists. He was probably best known for a thesis, proposed independently by Turing, that holds that a function is calculable if it is recursive (able to be repeated) and, therefore, that problems are either solvable or unsolvable by mechanical methods of computation. The so-called Church-Turing thesis helped to extend the work of Kurt Gödel, who in 1931 theorized that there are truths in elementary mathematics that cannot be proved or disproved on the basis of the axioms within that system. In 1936 Church helped found the Journal of Symbolic Logic, compiling an exhaustive bibliography on logic for its first issue; he remained editor until 1979. He also wrote the textbook Introduction to Mathematical Logic (1956).* * *
Universalium. 2010.
