Mathematics Department

Math Department Colloquium

Thu, Mar 22–Thu, Mar 22

1:00 PM– 2:00 PM

Abstract: On the space of integer linear combinations oforiented edges of a finite graph, consider the linear operator T thatassigns to an edge the sum of its outgoing edges. The operator wasconstructed by Bass and Hashimoto in connection with the zeta functionof the graph. I will show an elementary way to calculate the kernel andcokernel of 1-T on these integral spaces, and then apply this to aclassification problem in the theory of C*-algebras. Joint work withOliver Lorscheid (Utrecht) and Matilde Marcolli (MPIM Bonn).