Monodromy groups and regular covers of abstract polytopes

2016-01-04
10:00-11:00
FAMNIT-POŠTA
Gordon Williams (University of Alaska Fairbanks, USA)
Monodromy groups and regular covers of abstract polytopes

The objective of this talk is to provide an introduction to several open problems about the monodromy groups of abstract polytopes and how they relate to the study of coverings of abstract polytopes by regular abstract polytopes.

Abstract polytopes are a generalization of convex polytopes to purely combinatorial objects, as partially ordered sets satisfying some relatively straightforward constraints. The most symmetric type of abstract polytopes, the regular abstract polytopes, have been studied extensively, and their analysis has been greatly facilitated by the study of their automorphism groups. However, non-regular abstract polytopes are poorly understood, in part because their automorphism group doesn’t give enough information about their structure. To begin to investigate non-regular polytopes, we have used two main tools: representation of non-regular polytopes as quotients of regular polytopes, and analysis of the “monodromy group” of the polytope, which encodes combinatorially the connective structure of the polytope. There are important relationships between these two representations, and understanding the relationship motivates many interesting problems in the theory of non-regular abstract polytopes.

This talk will assume no background understanding of either abstract polytopes or monodromy groups. I will provide basic definitions and examples to illustrate both important basic facts about what we have learned about quotient representations and monodromy groups, as well as facilitate introducing open problems in the area.