## Number Theory Seminar: Karen Yeats

- Date: 12/01/2011
- Time: 16:10

University of British Columbia

The c_2 invariant of Feynman graphs

Last year Francis Brown and Oliver Schnetz defined the c_2 invariant of a graph. Let p be prime, take the Kirchhoff polynomial of a graph, and count points on the variety of this polynomial over the finite field with p elements. For the graphs of interest to us, this point count will be divisible by p^2 and the result modulo p is the c_2 invariant at p.This invariant has important things to say about the Feynman integrals of scalar Feynman graphs, and links together the combinatorial and algebro-geometric approaches to understanding Feynman integrals.In this talk I will describe this setup and then explain some joint results with Francis Brown and Oliver Schnetz concerning the c_2 invariant of graphs with subdivergences.

4:10-5:00pm in WMAX 216