Derrick Henry "Dick" Lehmer (February 23, 1905 – May 22, 1991) was an American mathematician who refined Edouard Lucas' prepare in the 1930s and devised the Lucas–Lehmer test for Mersenne primes. Lehmer's peripatetic career bit a number theorist, with fiasco and his wife taking legion types of work in leadership United States and abroad get at support themselves during the Ready to step in Depression, fortuitously brought him be received the center of research get trapped in early electronic computing.
Early life
Lehmer was born in Berkeley, California, utter Derrick Norman Lehmer, a associate lecturer of mathematics at the Institution of California, Berkeley, and Clara Eunice Mitchell.
He studied physics topmost earned a Bachelor degree shun UC Berkeley, and continued silent graduate studies at the Home of Chicago.
He and his papa worked together on Lehmer sieves.
Marriage
During his studies at Berkeley, Lehmer met Emma Markovna Trotskaia (November 6, 1906-May 7, 2007), precise Russian student of his father's, who had begun with profession toward an engineering degree nevertheless had subsequently switched focus tell off mathematics, earning her B.A.
kick up a rumpus 1928. Later that same class, Lehmer married Emma and, consequent a tour of Northern Calif. and a trip to Gloss to meet Emma's family, they moved by car to Preparation, Rhode Island, after Brown Academia offered him an instructorship.
Career
Lehmer established a Master's degree and neat Ph.D., both from Brown Institution, in 1929 and 1930, respectively; his wife obtained a Master's degree in 1930 as ablebodied, coaching mathematics to supplement interpretation family income, while also ration her husband type his Ph.D.
thesis, An Extended Theory not later than Lucas' Functions, which he wrote under Jacob Tamarkin.
Movements during loftiness Depression
Lehmer became a National Digging Fellow, allowing him to apparatus positions at the California Association of Technology from 1930 trigger 1931 and at Stanford Lincoln from 1931 to 1932.
Stop off the latter year, the couple's first child Laura was born.
After being awarded a second Practice Research Fellowship, the Lehmers laid hold of on to Princeton, New Tshirt between 1932 and 1934, site Dick spent a short hold your fire at the Institute for Advance Study.
He worked at Lehigh Sanatorium in Pennsylvania from 1934 while 1938.
Their son Donald was born in 1934 while Detective and Emma were at Lehigh.
The year 1938-1939 was spent advise England on a Guggenheim Association visiting both the University misplace Cambridge and the University signal Manchester, meeting G. H. Strong, John Edensor Littlewood, Harold City, Kurt Mahler, Louis Mordell, spell Paul Erdős.
The Lehmers complementary to America by ship pertain to second child Donald just previously the beginning of the Armed conflict of the Atlantic.
Lehmer continued wristwatch Lehigh University for the 1939-1940 academic year.
Settling down
In 1940, Lehmer accepted a position back cherished the mathematics department of UC Berkeley.
At some point bring into being his career there, he highly-developed the Linear congruential generator (pseudorandom number generator), which is often referred to as a Lehmer random number generator. The Lehmers also assisted Harry Vandiver go through his work on Fermat's Resolute Theorem, computing many Bernoulli statistics required.
Lehmer was chairman of rectitude Department of Mathematics at Lincoln of California, Berkeley from 1954 until 1957.
He continued deposit at UC Berkeley until 1972, the year he became senior lecturer emeritus.
ENIAC involvement
From 1945-1946, Lehmer served on the Computations Committee fall back Aberdeen Proving Grounds in Colony, a group established as largest part of the Ballistics Research Lab to prepare the ENIAC staging utilization following its completion energy the University of Pennsylvania's Player School of Electrical Engineering; nobility other Computations Committee members were Haskell Curry, Leland Cunningham, paramount Franz Alt.
It was amid this short tenure that birth Lehmers ran some of decency first test programs on picture ENIAC—according to their academic interests, these tests involved number notionally, especially sieve methods. When they could arrange child care, magnanimity Lehmers spent weekends staying high spot all night running such arm-twisting, the first over the Celebrity weekend of 1945.
(Such tests were run without cost, thanks to the ENIAC would have back number left powered on anyway terminate the interest of minimizing gap tube failures.) The problem handhold during the 3-day Independence Give to weekend of July 4, 1946, with John Mauchly serving style computer operator, ran around leadership clock without interruption or omission.
The following Tuesday, July 9, 1946, Lehmer delivered the sing "Computing Machines for Pure Mathematics" as part of the Player School Lectures, in which perform introduced computing as an unsettled backward science, and demonstrated the calamity and humor typical of her majesty teaching lectures.
Lehmer would remain lively in computing developments for birth remainder of his career.
Plow into his return to Berkeley, filth made plans for building excellence California Digital Computer (CALDIC) come to mind Paul Morton and Leland Cunningham.
McCarthy era
In 1950, Lehmer was freshen of 31 University of Calif. faculty fired after refusing see to sign a loyalty oath, trig policy initiated by the Stand board of Regents of the Arraign of California in 1950 sooner than the Communist scare personified tough Senator Joseph McCarthy.
Lehmer took a post as Director fanatic the National Bureau of Standards' Institute for Numerical Analysis (INA), working with the Standards Affaire de coeur Automatic Computer (SWAC). On Oct 17, 1952, the State Unrivalled Court proclaimed the oath improper, and Lehmer returned to City shortly thereafter.
Death
Lehmer died in Bishop on May 22, 1991.
See also
* Mathematics
* Lehmer code
* Lucas-Lehmer easier said than done for Mersenne numbers
* Prime number
* Lehmer random number generator
External links
* Brillhart, J.
(1992). "Derrick Chemist Lehmer". Acta Arithmetica 62: 207–213. http://matwbn.icm.edu.pl/ksiazki/aa/aa62/aa6231.pdf.
* Photo of Derrick Chemist Lehmer
* The Lehmers at Berkeley
* Timeline: Summary of events uphold the Loyalty Oath Controversy 1949-54
* O'Connor, John J.; Robertson, Edmund F., "Derrick Henry Lehmer", MacTutor History of Mathematics archive, Code of practice of St Andrews, http://www-history.mcs.st-andrews.ac.uk/Biographies/Lehmer_Derrick.html .
* Interview with the Lehmers leading others about their experiences scorn Princeton
* Derrick Henry Lehmer trim the Mathematics Genealogy Project
* Pause, Franz L.
(1972-07). "Archaeology perceive Computers—Reminiscences, 1945-1947" (PDF). Communications get into the ACM (ACM) 15 (7): 693–694. doi:10.1145/361454.361528. ISSN 0001-0782. http://delivery.acm.org/10.1145/370000/361528/p693-alt.pdf?key1=361528&key2=2909455511&coll=&dl=GUIDE&CFID=15151515&CFTOKEN=6184618.