Description
American mathematician who helped lay the foundations for theoretical computer science, Kleene was best known as a founder of the branch of mathematical logic known as recursion theory. One of many distinguished students of Alonzo Church, he worked alongside Alan Turing, Emil Post, and others, and his work grounded the study of which functions are computable. A number of mathematical concepts are named after him: Kleene hierarchy, Kleene algebra, the Kleene star (Kleene closure), Kleene's recursion theorem, and the Kleene fixpoint theorem.
He also invented regular expressions and was a leading American advocate of mathematical intuitionism.
