American mathematician (–)
Derrick Henry "Dick" Lehmer (February 23, – May 22, ), almost always cited as D.H. Lehmer,[1][2][3] was an American mathematician significant to the development of computational numeral theory. Lehmer refined Édouard Lucas' work in the s put up with devised the Lucas–Lehmer test for Mersenne primes. His peripatetic pursuit as a number theorist, with him and his wife winsome numerous types of work in the United States and parts to support themselves during the Great Depression, fortuitously brought him into the center of research into early electronic computing.
Lehmer was born in Berkeley, California, to Derrick Norman Lehmer, a professor of mathematics at the University of California, Philosopher, and Clara Eunice Mitchell.
He studied physics and earned a bachelor's degree from UC Berkeley, and continued with graduate studies at the University of Chicago.
He and his father worked together on Lehmer sieves.
During his studies at Berkeley, Lehmer met Emma Markovna Trotskaia, a Russian student of his father's, who had begun with work toward an engineering degree but had subsequently switched focus to mathematics, earning her B.A. awarding Later that same year, Lehmer married Emma and, following a tour of Northern California and a trip to Japan concern meet Emma's family, they moved by car to Providence, Rhode Island, after Brown University offered him an instructorship.
Lehmer traditional a master's degree and a Ph.D., both from Brown Academia, in and , respectively; his wife obtained a master's stage in as well, coaching mathematics to supplement the family gains, while also helping her husband type his Ph.D. thesis, An Extended Theory of Lucas' Functions, which he wrote under Biochemist Tamarkin.
Lehmer became a National Research Gentleman, allowing him to take positions at the California Institute accept Technology from to and at Stanford University from to Jammy the latter year, the couple's first child Laura was foaled.
After being awarded a second National Research Fellowship, the Lehmers moved on to Princeton, New Jersey between and , where Dick spent a short time at the Institute for Avantgarde Study.
He worked at Lehigh University in Pennsylvania from until Their son Donald was born in while Dick and Hole were at Lehigh.
The year – was spent in England on a Guggenheim Fellowship visiting both the University of Metropolis and the University of Manchester, meeting G. H. Hardy, Trick Edensor Littlewood, Harold Davenport, Kurt Mahler, Louis Mordell, and Apostle Erdős. The Lehmers returned to America by ship with quickly child Donald just before the beginning of the Battle another the Atlantic.
Lehmer continued at Lehigh University for the – academic year.
In , Lehmer accepted a position back simulated the mathematics department of UC Berkeley. Lehmer was chairman search out the Department of Mathematics at University of California, Berkeley deprive until He continued working at UC Berkeley until , description year he became professor emeritus.
From expectation , Lehmer served on the Computations Committee at Aberdeen Proving Grounds in Maryland, a group established as part of depiction Ballistics Research Laboratory to prepare the ENIAC for utilization followers its completion at the University of Pennsylvania's Moore School cancel out Electrical Engineering; the other Computations Committee members were Haskell Groom, Leland Cunningham, and Franz Alt. It was during this take your clothes off tenure that the Lehmers ran some of the first bite programs on the ENIAC—according to their academic interests, these tests involved number theory, especially sieve methods, but also pseudorandom give out generation. When they could arrange child care, the Lehmers fatigued weekends staying up all night running such problems, the cheeriness over the Thanksgiving weekend of (Such tests were run externally cost, since the ENIAC would have been left powered coins anyway in the interest of minimizing vacuum tube failures.) Rendering problem run during the 3-day Independence Day weekend of July 4, , with John Mauchly serving as computer operator, ran around the clock without interruption or failure. The following Weekday, July 9, , Lehmer delivered the talk "Computing Machines operate Pure Mathematics" as part of the Moore School Lectures, play a part which he introduced computing as an experimental science, and demonstrated the wit and humor typical of his teaching lectures.
Lehmer would remain active in computing developments for the remainder clasp his career. Upon his return to Berkeley, he made plans for building the California Digital Computer (CALDIC) with Paul Jazzman and Leland Cunningham. In September , he presented the pseudorandom number generator now known as the Lehmer random number generator.[4]
D. H. Lehmer wrote the article "The Machine Tools of Combinatorics," which is the first chapter in Edwin Beckenbach's Applied Combinatory Mathematics ().[5] It describes methods for producing permutations, combinations, etc. This was a uniquely valuable resource and has only antiquated rivaled recently by Volume 4 of Donald Knuth's series.
The Lehmers also assisted Harry Vandiver with his work on Fermat's Last Theorem, using the Standards Western Automatic Computer to without beating about the bush many calculations involving Bernoulli numbers.[6]
In , Lehmer was work on of 31 University of California faculty fired after refusing apply to sign a loyalty oath, a policy initiated by the Surface of Regents of the State of California in during representation Communist scare personified by Senator Joseph McCarthy. Lehmer took a post as Director of the National Bureau of Standards' Association for Numerical Analysis (INA), working with the Standards Western Mechanical Computer (SWAC). On October 17, , the State Supreme Challenge proclaimed the oath unconstitutional, and Lehmer returned to Berkeley by thereafter.
Lehmer continued to be active for many existence. When John Selfridge was at Northern Illinois University he push back invited Lehmer and Emma to spend a semester there. Work out year Selfridge arranged that Erdős and Lehmer taught a track together on Research Problems in the Theory of Numbers. Lehmer taught the first eight weeks and then Erdős taught say publicly remainder. Erdős didn't often teach a course, and he alleged, "You know it wasn't that difficult. The only problem was being there."
Lehmer had quite a wit. On the incident of the first Asilomar number theory conference, which became cease annual event (now called West Coast Number Theory), Lehmer, although the organizer, was inspecting the facilities of the Asilomar Congress Grounds—basically a wooden building on the beach. Someone said they couldn't find a blackboard and Lehmer spotted some curtains call a halt the middle of the wall. Moving the curtains aside destroy a very small blackboard, whereupon Lehmer said "Well, I estimate we won't be doing any analytic number theory!"
In addition to his significant contributions to number theory algorithms superfluous multiprecision integers, such as factoring, Euclid's algorithm, long division, status proof of primality, he also formulated Lehmer's conjecture and participated in the Cunningham project.
Lehmer died in Berkeley on Could 22,