Ian Morris gives Number Theory Seminar at Oxford University

1780120__OxfordMaths_Aerial-webIan Morris visited the Mathematical Institute, University of Oxford, yesterday (Thursday 26 November) to give a talk in the seminar of the Number Theory Group. His talk was on “The central limit theorem for the number of steps in the Euclidean algorithm“.  Abstract: The number of steps required by the Euclidean algorithm to find the greatest common divisor of a pair of integers u,v with 1<u<v<n has been investigated since at least the 16th century, with an asymptotic for the mean number of steps being found independently by H. Heilbronn and J.D. Dixon in around 1970. It was subsequently shown by D. Hensley in 1994 that the number of steps asymptotically follows a normal distribution about this mean. Existing proofs of this fact rely on extensive effective estimates on the Gauss-Kuzman-Wirsing operator which run to many dozens of pages. I will describe how this central limit theorem can be obtained instead by a much shorter Tauberian argument.