# Joint IAS/PU Number Theory

## Rational curves on elliptic surfaces

Douglas Ulmer
Georgia Institute of Technology
May 5, 2016
Given a non-isotrivial elliptic curve $E$ over $K = \mathbb F_q(t)$, there is always a finite extension $L$ of $K$ which is itself a rational function field such that $E(L)$ has large rank. The situation is completely different over complex function fields: For "most" $E$ over $K = \mathbb C(t)$, the rank $E(L)$ is zero for any rational function field $L = \mathbb C(u)$. The yoga that suggests this theorem leads to other remarkable statements about rational curves on surfaces generalizing a conjecture of Lang.

## Iwasawa theory for the symmetric square of a modular form

David Loeffler
University of Warwick
March 10, 2016
Iwasawa theory is a powerful technique for understanding the link between the special values of L-functions and arithmetic objects (such as class groups of number fields, or Mordell-Weil groups of elliptic curves). In this talk I'll discuss what Iwasawa theory predicts for the symmetric square L-function attached to a modular form; and I'll describe some recent results (joint with Sarah Zerbes) confirming some of these conjectures, using the method of Euler systems.