Alan Baker (mathematician)

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Alan Baker

FRS
Alan-Baker.jpg
Born(1939-08-19)19 August 1939
London, England
Died4 February 2018(2018-02-04) (aged 78)
Cambridge, England
Alma mater University College London
University of Cambridge
Known for Number theory
Diophantine equations
Baker's theorem
Baker–Heegner–Stark theorem
Awards Fields Medal (1970)
Adams Prize (1972)
Scientific career
Fields Mathematics
Institutions University of Cambridge
Thesis Some Aspects of Diophantine Approximation  (1964)
Doctoral advisor Harold Davenport
Doctoral students John Coates
Yuval Flicker
Roger Heath-Brown
David Masser
Cameron Stewart

Alan Baker FRS [1] (19 August 1939 – 4 February 2018 [2] ) was an English mathematician, known for his work on effective methods in number theory, in particular those arising from transcendental number theory.

Contents

Life

Alan Baker was born in London on 19 August 1939. He attended Stratford Grammar School, East London, and his academic career started as a student of Harold Davenport, at University College London and later at Trinity College, Cambridge, where he received his PhD. [3] He was a visiting scholar at the Institute for Advanced Study in 1970 when he was awarded the Fields Medal at the age of 31. [4] In 1974 he was appointed Professor of Pure Mathematics at Cambridge University, a position he held until 2006 when he became an Emeritus. He was a fellow of Trinity College from 1964 until his death. [3]

His interests were in number theory, transcendence, linear forms in logarithms, effective methods, Diophantine geometry and Diophantine analysis.

In 2012 he became a fellow of the American Mathematical Society. [5] He has also been made a foreign fellow of the National Academy of Sciences, India. [6]

Research

Baker generalised the Gelfond–Schneider theorem, which itself is a solution to Hilbert's seventh problem. [7] Specifically, Baker showed that if are algebraic numbers (besides 0 or 1), and if are irrational algebraic numbers such that the set is linearly independent over the rational numbers, then the number is transcendental.

Baker made significant contributions to several areas in number theory, such as the Gauss class number problem, [8] diophantine approximation, and to Diophantine equations such as the Mordell curve. [9] [10]

Selected publications

Honours and awards

Related Research Articles

In mathematics, a transcendental number is a real or complex number that is not algebraic – that is, not the root of a non-zero polynomial of finite degree with rational coefficients. The best-known transcendental numbers are π and e.

<span class="mw-page-title-main">Diophantine approximation</span> Rational-number approximation of a real number

In number theory, the study of Diophantine approximation deals with the approximation of real numbers by rational numbers. It is named after Diophantus of Alexandria.

In mathematics, a transcendental function is an analytic function that does not satisfy a polynomial equation, in contrast to an algebraic function. In other words, a transcendental function "transcends" algebra in that it cannot be expressed algebraically using a finite amount of terms.

In number theory, the Heegner theorem establishes the complete list of the quadratic imaginary number fields whose rings of integers are principal ideal domains. It solves a special case of Gauss's class number problem of determining the number of imaginary quadratic fields that have a given fixed class number.

Hilbert's seventh problem is one of David Hilbert's list of open mathematical problems posed in 1900. It concerns the irrationality and transcendence of certain numbers.

In mathematics, the Gelfond–Schneider theorem establishes the transcendence of a large class of numbers.

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Transcendental number theory is a branch of number theory that investigates transcendental numbers, in both qualitative and quantitative ways.

<span class="mw-page-title-main">Schanuel's conjecture</span> Conjecture on the transcendence degree of field extensions to the rational numbers

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In transcendental number theory, a mathematical discipline, Baker's theorem gives a lower bound for the absolute value of linear combinations of logarithms of algebraic numbers. The result, proved by Alan Baker, subsumed many earlier results in transcendental number theory and solved a problem posed by Alexander Gelfond nearly fifteen years earlier. Baker used this to prove the transcendence of many numbers, to derive effective bounds for the solutions of some Diophantine equations, and to solve the class number problem of finding all imaginary quadratic fields with class number 1.

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In mathematics, the analytic subgroup theorem is a significant result in modern transcendental number theory. It may be seen as a generalisation of Baker's theorem on linear forms in logarithms. Gisbert Wüstholz proved it in the 1980s. It marked a breakthrough in the theory of transcendental numbers. Many longstanding open problems can be deduced as direct consequences.

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References

  1. Masser, David (2023). "Alan Baker. 19 August 1939—4 February 2018". Biographical Memoirs of Fellows of the Royal Society. 74.
  2. Trinity College website, retrieved 5 February 2018
  3. 1 2 "BAKER, Prof. Alan" . Who's Who & Who Was Who . Vol. 2019 (online ed.). A & C Black.(Subscription or UK public library membership required.)
  4. Institute for Advanced Study: A Community of Scholars Archived 6 January 2013 at the Wayback Machine
  5. List of Fellows of the American Mathematical Society, retrieved 2012-11-03.
  6. "National Academy of Sciences, India: Foreign Fellows". Archived from the original on 18 February 2017. Retrieved 2 June 2018.
  7. Biography in Encyclopædia Britannica. http://www.britannica.com/eb/article-9084909/Alan-Baker
  8. Goldfeld, Dorian (1985). "Gauss' class number problem for imaginary quadratic fields". Bulletin of the American Mathematical Society. 13 (1). American Mathematical Society (AMS): 23–37. doi: 10.1090/s0273-0979-1985-15352-2 . ISSN   0273-0979.
  9. Masser, David (2021). "Alan Baker, FRS, 1939–2018". Bulletin of the London Mathematical Society. 53 (6). Wiley: 1916–1949. doi: 10.1112/blms.12553 . ISSN   0024-6093. S2CID   245627886.
  10. Wüstholz, Gisbert (2019). "Obituary of Alan Baker FRS". Acta Arithmetica. 189 (4). Institute of Mathematics, Polish Academy of Sciences: 309–345. doi:10.4064/aa181211-14-12. ISSN   0065-1036. S2CID   197494318.
  11. Stolarsky, Kenneth B. (1978). "Review: Transcendental number theory by Alan Baker; Lectures on transcendental numbers by Kurt Mahler; Nombres transcendants by Michel Waldschmidt" (PDF). Bull. Amer. Math. Soc. 84 (8): 1370–1378. doi: 10.1090/S0002-9904-1978-14584-4 .