Ernst Sejersted Selmer

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Ernst Sejersted Selmer (born February 20, 1920 in Oslo ; † November 8, 2006 ) was a Norwegian mathematician and computer engineer.

He was the son of the Germanist Ernst Westerlund Selmer (1890-1971), who was a professor at the University of Oslo. Selmer's grandfather Christian August Selmer was the Norwegian Minister of State. Selmer's mathematical talent was already noticed at school, as was that of his brother Nicolay (who died in 1943 while training as a bomber pilot). As a student of natural sciences and engineering, he published on prime numbers. Under the German occupation, the universities were closed in 1943 and he fled to Sweden. During World War II he worked as a cryptologist in London. In 1945 he received his candidate degree and married. In 1946 he became a university lecturer (lecturer) in Oslo, and in 1948 he published an analysis textbook. For his doctoral thesis, completed in 1951, he dealt with Diophantine equations of the third degree ( with integer coefficients a, b, c). Using the example of the equation for , he showed that the Hasse principle no longer applies here (in contrast to the quadratic case): The equation has no non-trivial solution in the integers, but has local (modulo of all integers and in the real Numbers). The result was expanded by John Cassels , whom Selmer visited in Cambridge in 1949. Cassels later named a group that played a role in obstruction to the Hasse principle after Selmer Selmer group . It also plays a role in Andrew Wiles ' proof of the Fermat conjecture.

1951-52 he was a Rockefeller Fellow in the US at the Institute for Advanced Study in Princeton, where he will be working on the IAS machine of John von Neumann was involved. He was also involved in the construction of the Datatron computer (Burroughs 205) at the Consolidated Engineering Corporation (CEC) in Los Angeles . Most of the logic came from him. In 1953 he applied for a US patent for electronic adding logic, which was granted in 1960. Back then he also used computers for his number theoretic calculations.

From 1956 until his retirement in 1990 he was a professor at the University of Bergen . 1960 to 1968 he was vice dean and dean of his faculty, interrupted by a sabbatical year in Cambridge in 1964/65. He not only built up pure mathematics in Bergen, but also the science faculty and the computer center. He was also significantly involved in expanding data processing at the national level. An algorithm he developed is used in Norway to control the population's identification numbers. In 2004 he suffered a stroke.

In the 1940s he published on prime numbers, e.g. B. 1942 a table of twin primes up to 200,000.

Selmer polynomials were also named after him. This resulted from Selmer's occupation (1956) with the factorization of polynomials of the form into polynomials with integer coefficients. This was expanded by Wilhelm Ljunggren and Andrzej Schinzel .

In the 1960s he returned to mathematics, which arose from his interest in cryptography (linear recursion and periodic sequences). He kept in contact with NATO's cryptographic services. Later the Selmer Center at the University of Bergen was named after him, where research into cryptography and coding theory is carried out. From the mid-1970s he dealt with combinatorial (additive) number theory (such as the postage stamp problem ). He worked with Gerd Hofmeister's group in Mainz.

He was a member of the Norwegian Academy of Sciences. In 1983 he became a knight of the Order of St. Olav, 1st class.

1954 to 1978 he was editor of the Nordisk Matematisk Tidskrift.

His daughter Johanne-Sophie Selmer was a microbiologist and taught at Karlstad University . His brother Knut (1924–2009) was a professor of legal informatics in Oslo.

Fonts (selection)

  • Selmer: The Diophantine equation ", Acta Mathematica, Volume 85, 1951, pp. 203-362

Web links

Individual evidence

  1. ↑ Ernst Selmer, From the Memoirs of a Norwegian Cryptologist, Eurocrypt 1993, pp. 142-150
  2. ↑ Selmer Group , Planetmath
  3. ^ Cassels, Arithmetic on curves of genus 1. III. The Tate-Šafarevič and Selmer groups, Proceedings of the London Mathematical Society, Third Series, Volume 12, 1962, pp. 259-296
  4. ↑ Selmer Center
personal data
SURNAME Selmer, Ernst Sejersted
BRIEF DESCRIPTION Norwegian mathematician
DATE OF BIRTH February 20, 1920
PLACE OF BIRTH Oslo
DATE OF DEATH November 8, 2006