Speaker: Sadok Kallel (American University of Sharjah, UAE)

Title: Combinatorial Invariants of Stratified Spaces

Abstract: We construct a Grothendieck ring for poset-stratified spaces and use it to compute the topological Euler characteristic of a number of constructions in topology and geometry. This ring is defined on a suitable essentially small subcategory of Top and offers a flexible real analog of the Grothendieck ring of varieties in algebraic geometry. A number of applications are given to orbifolds and to spaces stratified by configuration spaces, like chromatic configuration spaces, bounded multiplicity configurations or finite subset spaces.