Speaker: Alexey Ovchinnikov, Queens College (CUNY) Title: Complexity of elimination for systems of differential equations Date: May 3, 2016 Place: 1314 Warren Weaver Hall Time: 6-7pm Abstract: We will discuss complexity bounds for the effective Nullstellensatz for systems of polynomial PDEs. These are uniform bounds for the number of differentiations to be applied to all equations of a system of PDEs in order to discover algebraically whether it is consistent (i.e., has a solution in a field). The bounds are functions of the degrees and orders of the equations of the system and the numbers of dependent and independent variables in them. Among several bottlenecks in this problem is calculation of a projection of a variety. We will also discuss another approach to simplifying systems of polynomial PDEs, which avoids this bottleneck, as well as the associated complexity bounds.