Klaus Friedrich Roth, (pronounced /ˈroʊθ/) (born 29 October 1925) is a British mathematician known for work on diophantine approximation, the large sieve, and irregularities of distribution. He was born in Breslau (then in Prussia, now in Poland) but raised and educated in the UK. He graduated from Peterhouse, Cambridge in 1945. In 1946 he began research at University College London, under the supervision of Theodor Estermann.

In 1952, Roth proved that subsets of the integers of positive density must contain infinitely many arithmetic progressions of length three, thus establishing the first non-trivial case of what is now known as Szemerédi's theorem. His definitive result, now known usually as the Thue–Siegel–Roth theorem, but also just Roth's theorem, dates from 1955, when he was a lecturer at University College London. He was awarded a Fields Medal in 1958 on the strength of it. He became a professor at University College London in 1961, and moved to a chair at Imperial College London in 1966, a position he retained until official retirement at 1988. He then changed his status to visiting professor and remained at Imperial College until 1996. He is currently the oldest living Fields Medallist (2009).

External links

* O'Connor, John J.; Robertson, Edmund F., "Klaus Roth", MacTutor History of Mathematics archive, University of St Andrews, http://www-history.mcs.st-andrews.ac.uk/Biographies/Roth_Klaus.html .
* Klaus Roth at the Mathematics Genealogy Project