Name: Stephen Kleene

Born: January 5, 1909, in Hartford, Connecticut USA

Death: January 25, 1994 (Age: 85)

  • American mathematician who co-founded the branch of mathematical logic known as recursion theory, with Alan Turing, Emil Post, and others.
  • His worked contributed to the foundations of theoretical computer science.
  • Inventor of regular expressions in mathematics.

Significant publications

  • Origins of Recursive Function Theory (1981).
  • Mathematical Logic (1967).
  • The Foundations of Intuitionistic Mathematics (1965).
  • Representation of Events in Nerve Nets and Finite Automata (1956).
  • Introduction to Metamathematics (1952).

Honors and awards

  • National Medal of Science (1990).
  • Leroy P. Steele Prize (1983).
  • Numerous mathematical concepts are named after him: Kleene hierarchy, Kleene algebra, the Kleene star (Kleene closure), Kleene’s recursion theorem and the Kleene fixpoint theorem.

Quotes

“I had some hesitations about philosophy because, if you worked out a philosophical theory, it was hard to know whether you were going to be able to prove it or whether other theories had just as good a claim on belief.”

  • Alan Turing
  • Emil Post