Emma Trotskaya Lehmer

Mathematician Emma Trotskaya Lehmer, for many years a vital member of the University of California, Berkeley, mathematics community diead on may 7 at the age of 100.Lehmer was an accomplished mathematician who specialized in number theory, publishing 56 papers during her lifetime, 21 of them with her husband, Derrick Henry "Dick" Lehmer, a UC Berkeley professor of mathematics who died in 1991. The couple founded in 1969 the annual West Coast Number Theory Meeting, "one of their most enduring contributions to the world of mathematicians," wrote John D. Brillhart, a professor emeritus of mathematics at the University of Arizona in Tucson who was a former student of Lehmer's husband.During the war, Lehmer's husband, a leading authority on number theory and computation, helped develop and test the first modern digital computer, called the ENIAC (Electronic Numerical Integrator and Calculator), at the Aberdeen Proving Ground in Maryland. Though the ENIAC was designed to calculate ballistic trajectories, Emma and her husband were able to use it occasionally on weekends to do calculations impossible with paper and pencil, such as factoring numbers to find large primes - numbers divisible only by themselves and one. Dick Lehmer and his father, UC Berkeley mathematics professor Derrick Norman Lehmer, had earlier built an electro-mechanical sieve capable of factoring very large numbers - a machine that they displayed at the Chicago World's Fair in 1933. Lehmer was born Emma Trotskaya in Samara, Russia, on Nov. 6, 1906, and moved with her family in 1910 to Harbin, Manchuria, where her father represented a Russian sugar company. Schooled at home until the age of 14, when a local school finally opened, she was inspired to pursue engineering and mathematics by an exceptional high school teacher and planned on continuing her education in Russia. Emma Lehmer frequently collaborated with her husband and her father-in-law. The three developed methods for computer computations to assist in solving number theory problems, and in 1930 they applied to the Carnegie Institution for funds to construct a machine that would, according to their proposal, check "a million numbers in about three minutes" in order to find factors of large whole numbers.