NORTHEASTERN UNIVERSITY
MATHEMATICS DEPARTMENT
 
Geometry-Algebra-Singularities-Combinatorics 
Seminar
 
 
The Buchsbaum-Rim multiplicity, modules which are direct sums of ideals, and the volumes of polyhedra 
 
 

Terry Gaffney

(Northeastern University)
 
 

Northeastern University

509 Lake Hall

1:30 p.m., Monday, September 27, 1999

 
 
Abstract:  Buchsbaum and Rim developed the notion of the multiplicity of a module which bears their name in the mid-60's. This multiplicity plays an important role in the theory of equisingularity. Although much studied in recent years, it is still easy to ask questions whose answers are unknown. In this talk, we will discuss the multiplicity of an ideal, then of a module, and connect these notions to the geometry of polyhedra for monomial ideals and modules. We give a formula for the Buchsbaum-Rim multiplicity of a module which is a direct sums of ideals in terms of the "mixed multiplicities" of the summands. For monomial modules we show this formula relates the volume of the polyhedron associated with the module to the mixed covolumes of the polyhedra associated with the summands.  
 
Home Web page:  Alexandru I. Suciu  Created: September 20, 1999   
Comments to:  schenck@neu.edu URL: http://www.math.neu.edu/~GASC/gas/gaffney.html