Mapping class groupoids and Thompson's groups

Abstract

We introduce a groupoid ${\mathbf{\Pi MG}}}$, called the fundamental modular groupoid, which is a variant of Penner's mapping class groupoid. We study how it relates to the surface mapping class groups and Thompson's group $\mathsf T$. We also introduce larger groupoid $\mathbf{\Omega MG}$, which is related to outer automorphisms of free groups and Thompson's group $\mathsf V$ in a similar manner.