Nicholas (Nick) John Pippenger

Co-inventor of extendible hashing, Pippenger is recognized for a number of fundamental results widely used in theoretical computer science, database processing, and compiler optimization. He held a B.S. degree in Natural Sciences from Shimer College in Chicago, Illinois (1965) and a B.S., M.S., and Ph.D. in Electrical Engineering from the Massachusetts Institute of Technology (MIT) in 1967, 1969, and 1974 respectively. His research interests centered in theoretical computer science, but also extended into communication theory and mathematics.

Before joining the faculty at Princeton University, he worked for the MIT Instrumentation Laboratory (now the Charles Stark Draper Laboratory), IBM Research, and the University of British Columbia. He also taught at the University of British Columbia in Vancouver, Canada. In the Fall of 2006, Pippenger joined the faculty of Harvey Mudd College.

In 1987 he achieved the rank of IBM Fellow at Almaden IBM Research Center in San Jose, California. IBM Fellow is the highest honor a scientist, engineer, or programmer at IBM can achieve. In addition to his title of IBM Fellow, he has been a Fellow of the Royal Society of Canada (Academy of Science), a 1997 Fellow of the ACM (Association for Computing Machinery), and a Fellow of the IEEE (Institute of Electrical and Electronics Engineers). Pippenger has also been a member of the American Mathematical Society (AMS), becoming a Fellow in 2012, as well as a member of the MAA (Mathematical Association of America) and SIAM (Society for Industrial and Applied Mathematics).

The complexity class named Nick's Class (NC) by Stephen Cook is a class of problems quickly solvable on a parallel computer. It was so named for his research on circuits with polylogarithmic depth and polynomial size. Pippenger, along with Ronald Fagin, Jurg Nievergelt, and Ray Strong, invented extendible hashing, a database access technique in which the user is guaranteed no more than two page faults to locate the data associated with a given unique identifier, or key. Unlike conventional hashing, extendible hashing has a dynamic structure that grows and shrinks gracefully as the database grows and shrinks. Because it combines the speed of hashing with adaptable dynamic behavior, and because it is easy to understand and to program, extendible hashing became widely studied and widely implemented.

He is the author of "Theories of Computability", published by Cambridge University Press in 1997. Pippenger became one of the most recent mathematicians to write a technical article in Latin, when he published a brief derivation of a new formula for "e", an important mathematical constant that is the base of the natural logarithm. He is married to Maria Klawe, President of Harvey Mudd College.