Leigh Cobbs

collaborators

2 papers

math.RT2010

Classification of hyperbolic Dynkin diagrams, root lengths and Weyl group orbits

Lisa Carbone, Sjuvon Chung, Leigh Cobbs +4

We give a criterion for a Dynkin diagram, equivalently a generalized Cartan matrix, to be symmetrizable. This criterion is easily checked on the Dynkin diagram. We obtain a simple…

math.GR2009

Fundamental domains for congruence subgroups of SL2 in positive characteristic

Lisa Carbone, Leigh Cobbs, Scott H. Murray

In this work, we construct fundamental domains for congruence subgroups of $S L_{2} (F_{q} [t])$ and $P G L_{2} (F_{q} [t])$ . Our method uses Gekeler's description of the fundamental domains on t…