These are the slides of my talk at Bill Duke’s birthday conference held at ETH in Zurich. I later wrote an extended abstract of this talk. It includes a proof of the calculation of the mixed Hodge numbers of a hypergeometric motive. The original conjecture on Hodge numbers of is a paper of Corti and Golyshev. A proof was given by Fedorov.

These are the slides of my talk at the 2018 conference “Perspectives on the Riemann Hypothesis” held in Bristol.

These are the slides of my Beeger Lecture at the 2018 Dutch Mathematical Congress.

These are notes of a talk a gave in a workshop on the arithmetic of curves held in Barcelona in 2017.

These are the slides of my talk at the first Abel conference in honor of John Tate at the University of Minessota in 2011. It is a summary of my work with T. Hausel and E. Letellier.

These are slides of a talk of the late 2000’s (don’t remember where) on my early work with T. Hausel on character varieties. It has some details on the combinatorics involved in computing the key quantity $C_\tau$.

These are the slides of my talk at the 1998 Pacific Northwest Number Theory Meeting.

These are the slides of a talk I gave some time in 1997 on my joint work with Farshid Hajir on defining explicit elliptic units; basically trying, and to some degree succeeding, to tame the 24-th roots of unity that arise from the transformation formula of Dedekind’s eta function.

These are the notes of one my first research talks in the US, at OSU in the Spring of 1989. It is on my thesis (original, published versions).