Abstract
Buildings were originally introduced by Jacques Tits around the 1950s
as a geometric tool to study the semisimple Lie (and algebraic)
groups. By now, buildings have a very rich theory of their own; for
instance, they possess a "non-positively curved" cellular complex
structure, which makes them prominent objects of interest in geometric
group theory. In this talk, I will investigate certain combinatorial
analogues of geodesic rays in buildings (the "geodesic ray bundles")
and give some intuition about how they look like. Using recent results
of Huang, Sabok and Shinko, I will then derive some consequences on
the topic of hyperfinite group actions.