Stephen Cole Kleene

Born Jan. 5, 1909, in Hartford, Conn. American logician and mathematician.

Kleene received his Ph.D degree from Princeton University in 1934. In 1948 he became a professor at the University of Wisconsin (Madison). His principal works are devoted to the theory of algorithms and recursive functions and to problems of intuitionistic logic and mathematics. In particular he proved the equivalence of the concept of γ-definability of a function, which was introduced by A. Church, and general recursiveness. The concept introduced by Kleene of the (recursive) realizability of formulas lies at the basis of the intuitionistic interpretation of number-theoretic propositions. Kleene is the author of a series of widely known monographs on mathematical logic, the foundations of mathematics, and the theory of recursive functions.