Jon Kleinberg, Cornell professor of computer science, received the 2006 Rolf Nevanlinna Prize at the International Congress of Mathematicians in Madrid, Spain, for his "deep, creative and insightful contributions to the mathematical theory of the global information environment."

The prize has been awarded every four years since 1982 by the International Mathematics Union, in recognition of the most notable advances made in mathematics in the "information society" -- that is, the modern world as influenced by information technology. It is considered to be a computer-science oriented parallel to the prestigious Fields Medal, regarded as the equivalent of a Nobel Prize in mathematics.

The prize, a gold medal, was presented by King Juan Carlos of Spain at the opening session of the conference. On Aug. 25 Kleinberg presented a lecture associated with the award.

In 1996, Kleinberg introduced the idea of "authorities" and "hubs" on the Internet and devised algorithms to analyze their links to one another, which have greatly influenced how today's search engines operate. He has made major contributions to the theory of small-world networks (the origin of the term "six degrees of separation") that have applications in fields ranging from sociology to the design of peer-to-peer file-sharing networks. He developed a mathematical model to recognize "bursts" in data streams, showing what topics are receiving attention at a given time in a large collection of data, from national news to personal e-mail.

Kleinberg received his bachelor's degree from Cornell in 1993, and an S.M. degree (1994) and Ph.D. (1996) from the Massachusetts Institute of Technology. Among his distinctions are a Sloan Foundation fellowship, a Packard Foundation fellowship and the Initiatives in Research Award of the U.S. National Academy of Sciences. In 2005, Kleinberg received a MacArthur "genius" fellowship from the John D. and Catherine T. MacArthur Foundation.

In addition to the areas cited in the Nevanlinna Prize, Kleinberg works on problems in data mining, computer optimization, computational biology, geometric pattern matching and fault tolerance in distributed computing.