For Stephen Kleene, dedication and intelligence added up to a lifelong legacy in the field of mathematics. While working at the University of Wisconsin-Madison, Kleene, along with a group of mathematicians, founded the recursion theory — a branch of logic used to determine if a function is computable or not. Recursion theory laid the groundwork for modern computer science and still heavily influences the field today.

Many mathematical operations were named after the math professor including the Kleene hierarchy, Kleene algebra, Kleene star and the Kleene recursion theorem.

Kleene taught mathematics at the Institute of Advanced Study and Amherst College and finished his career at the University of Wisconsin-Madison. Though he technically retired in 1979, Kleene remained professor emeritus until his death in 1994.

In 1999, the University of Wisconsin-Madison renamed its math library the Stephen Cole Kleene Mathematics Library in honor of its famous faculty member.

By Rachel Warren