## Distinguished Lecture Series

Every year, the Distinguished Lecture Series (DLS) brings two to four eminent mathematicians to UCLA for a week or more to give a lecture series on their field, and to meet with faculty and graduate students.

The first lecture of each series is aimed at a general mathematical audience, and offers a rare opportunity to see the state of an area of mathematics from the perspective of one of its leaders.  The remaining lectures in the series are usually more advanced, concerning recent developments in the area.

Previous speakers of the DLS include: Peter Sarnak, Peter Schneider, Zhengan Weng, Etienne Ghys, Goro Shimura, Jean Bellissard, Andrei Suslin, Pierre Deligne, Michael Harris, Alexander Lubotzky, Shing-Tau Yau, Hillel Furstenberg, Robert R. Langlands, Clifford Taubes, Louis Nirenberg, Oded Schramm, Louis Nirenberg, I.M. Singer, Jesper Lutzen, L.H. Eliasson, Raoul Bott, Dennis Gaitsgory, Gilles Pisier, Gregg Zuckerman, Freydoon Shahidi, Alain Connes, Jöran Friberg, David Mumford, Sir Michael Atiyah, Jean-Michel Bismut, Jean-Pierre Serre, G. Tian, N. Sibony, C. Deninger, Peter Lax, and Nikolai Reshetikhin.

The DLS is currently supported by the Larry M. Wiener fund.

## Past Lectures

 University of Strasbourg Visit: 04/03/2013 to 04/20/2013 Rheinische Friedrich-Wilhelms-Universität Bonn Visit: 05/07/2013 to 05/09/2013 Eötvös Loránd University Visit: 05/28/2013 to 05/30/2013 Texas A&M Visit: 10/22/2013 to 10/26/2013 IAS, Princeton Visit: 10/30/2013 to 11/06/2013 Duke University / UC Berkeley Visit: 05/19/2014 to 05/23/2014 Cambridge University Visit: 10/04/2014 to 10/10/2014 Microsoft Research Visit: 11/03/2014 to 11/06/2014 Columbia University Visit: 02/17/2015 to 02/19/2015

## Upcoming Lectures

### Manjul Bhargava

#### Princeton University

Visit: 05/19/2015 to 05/21/2015

Lectures:

Values of integer polynomials

Polynomials are one of the most basic objects in mathematics - in particular, in number theory - yet the values they take remain largely mysterious!  In number theory, one is generally interested in polynomials having integer or rational number coefficients, and the values they take at integral or rational arguments.  In these three lectures, we examine three classical problems in number theory that involve understanding the values taken by integer polynomials, and give an overview of the long history of these problems and what is now known in each case.

May 19th  3pm

Lecture 1: The representation of integers by quadratic forms

The famous "Four Squares Theorem" of Lagrange asserts that any positive integer can be expressed as the sum of four square numbers. That is, the quadratic form $a^2 + b^2 + c^2 + d^2$ represents all (positive) integers. When does a general quadratic form represent all integers?  When does it represent all odd integers?  When does it represent all primes?  We show how all these questions turn out to have very simple and surprising answers.  In particular, we describe joint work with Jonathan Hanke that led to a proof of Conway's "290-Conjecture".

May 20th  3pm

Lecture 2: How likely is it for an integer polynomial to take a square value?

Understanding whether (and how often) a mathematical expression takes a square value is a problem that has fascinated mathematicians since antiquity.  After giving a survey of this problem, we will then concentrate on the case where the mathematical expression in question is simply a polynomial in one variable.  The main result in this case - proved just recently - is that if the degree of the polynomial is at least 6, then it is not very likely to take even a single square value!

May 21st  4:30pm

Lecture 3: The density of squarefree values taken by a polynomial

It is well known that the density of integers that are squarefree is $6/\pi^2$, giving one of the more intriguing occurrences of $\pi$ where one might not a priori expect it!  A natural next problem that has played an important role in number theory is that of understanding the density of squarefree values taken by an integer polynomial.  We survey a number of recent results on this problem for various types of polynomials - some of which use the ABC Conjecture and some of which do not.