Bristol University, May 12, 2008
Richard Weidmann, Heriot–Watt
Maps onto hyperbolic groups
Sela gives a complete description of Hom(H,G) where G is an arbitrary
finitely presented group and H is a torsion-free hyperbolic group.
Despite this fact it is known that there is no uniform algorithm that
decides whether Hom(H,G) contains an epimorphism; this is not even possible
if H is a free group. In this talk we discuss how methods similar to the
ones used to prove the various accessibility results can yield a
complete description of all epimorphisms from H to G where G is a good
hyperbolic group.
Added 13th May: Richard's recent papers here concern many of the topics he discussed.