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Biographies: Obituary -- Derrick Henry Lehmer Disclosure Number: IPCOM000129885D
Original Publication Date: 1995-Jun-30
Included in the Prior Art Database: 2005-Oct-07
Document File: 7 page(s) / 31K

Publishing Venue

Software Patent Institute

Related People

Harry D. Huskey: AUTHOR [+2]


Spartansburg, South Carolina

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Copyright ©; 1995 by the Institute of Electrical and Electronics Engineers, Inc. All rights reserved. Used with permission.

Biographies: Obituary -- Derrick Henry Lehmer

Harry D. Huskey

Spartansburg, South Carolina

Derrick Henry Lehmer, authority on number theory, early proponent of high-speed computers for mathematics, and designer, builder, and principal operator of pre-World War II mechanical number sieves, died in Berkeley, California, May 22, 1991, of natural causes. He was 86. I have divided this somewhat informal obituary of my friend, Dick, into two parts. First I describe his unique mechanical and electronic sieve computers, and then I tell the story of his life.

Part I: Sieve computers.

Mechanical sieve computers.

While an undergraduate at the University of California at Berkeley (UCB), Dick became interested in mechanizing the solution of linear congruence relations such as x = y(m). The problem is to find those integer values of x (y or m) such that x - y is a multiple of m. For example, if one can find an m different from 1 that satisfies 2257 = I(m), then the Mersenne conjecture that 2:57 -1 (a number of over 77 decimal digits) is prime is false.* 1

  (Image Omitted: Derrick Henry Lehmer Born February 23, 1905, Berkeley, Calif.; died May 22, 1991, Berkeley, Calif. Pre-World War II inventor of a mechanical method of solving congruence relations and finding prime numbers. Education: AB, University of California, Berkeley, 1927; ScM, mathematics, Brown University, 1929; PhD, mathematics, Brown University, 1930. Professional experience: assistant, Brown University, 1928; National Research Council fellow, California Institute of Technology, 1930-32; researcher, Institute for Advanced Study, Princeton N.J., 1933-34; instructor, Lehigh University, 1934-38; assistant professor, Lehigh University, 1938-40; professor, University of California, Berkeley, 1940-72, professor emeritus, 1972-death; mathematician, Aberdeen Proving Ground, 1945-46; director, Institute for Numerical Analysis

   (INA), National Bureau of Standards, and University of California, Los Angeles, 1951 -53. Honors and awards: Guggenheim fellow, Cambridge University, 1938-39; Fulbright lectureship in Australia, 1959; vice president, American Mathematical Society, 1953; vice president, Association for Computing Machinery, 1954-57; research professor, Miller Institute for Basic Research in Science at Berkeley, 1962-63.)

While still a graduate student (1928 to 1930), Dick, along with his wife, Emma, spent many hundreds of hours manually showing that 2157 - 1 was not prime. They worked independently, comparing numbers at each step, so as to be confident in their results.

1 * Marin Mersemle (1588-1648) was a monk, a French mathematician, a natural philosopher, and a theologian. He studied numbers of the form 2P - 1, where p is prime, and now such numbers are called Mersenne numbers.

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