Topology Seminar: Infinite volume and bounded cohomology

Seminar | August 28 | 4:10-5 p.m. | 3 Evans Hall

 James Farre, Yale University

 Department of Mathematics

In this talk, I will define bounded cohomology of groups with an emphasis on examples coming from computing the volumes of locally geodesic simplices in hyperbolic manifolds. We will see that the volume class associated to a hyperbolic structure identifies its geometrically infinite end invariants or those of the covering spaces associated to virtual fibers. We will also study the behavior of linear combinations of volume classes, and give a geometric interpretation of addition in some special cases.