"Euler Characteristics And Subgroup Control 
Of Homotopy"







AbstractIn the context of fusion theory, several categories arise that record different  aspects of the p-local data of finite groups.  By considering their classifying spaces, these  categories can be thought of as topological objects.  It is natural to ask whether the entire  category is needed to obtain the classifying space, or if there is a preferred collection of  subgroups where all the homotopical information is concentrated. In this talk, we will discuss this control of homotopy question, aided by Leinster's theory  of Euler characteristics of EI-categories.  We will review this theory and explain how it  can be used to suggest which subgroups are likely to determine the homotopy type in  different situations, then outline some of the proofs that control is actually achieved.  .



Date:  Monday, November  30, 2015

Time: 13.40 – 14:30

Place: Mathematics Seminar Room, SA-141


All are most cordially invited.
Tea and cookies will be served after the talk.