Date & Time: Tuesday, July 13, 2010, 14:30-15:30.
Venue: Ramanujan Hall
Title: Regularity of Ext Modules
Speaker: Manoj Kummini, Purdue University
Abstract: Let S be a polynomial ring and $I \subseteq S$ a homogeneous ideal. We look at bounds for the Castelnuovo-Mumford regularity of the Ext^i(S/I, \omega_S) modules where \omega_S is the graded canonical module of S). This provides some information on the growth of the Hilbert functions the Ext^i(S/I, \omega_S) modules, which, in turn, describe the growth of the Hilbert function of the local cohomology modules of S/I. We will show that reg(Ext^i(S/I, \omega_S)) \leq dim(Ext^i(S/I, \omega_S)), when I is a monomial ideal. This is joint work with S. Murai.