3 citations · 7 across the 10 of their papers we have counts for
10 papers
Scale and tidy subgroups for Weyl-transitive automorphism groups of buildings
Udo Baumgartner, James Parkinson, Jacqui Ramagge
We consider closed, Weyl-transitive groups of automorphisms of thick buildings. For each element of such a group, we derive a combinatorial formula for its scale and establish the…
Scale-multiplicative semigroups and geometry: automorphism groups of trees
Udo Baumgartner, Jacqui Ramagge, George A. Willis
A scale-multiplicative semigroup in a totally disconnected, locally compact group is one for which the restriction of the scale function on is multiplicative. The maximal s…
Hyperbolic groups have flat-rank at most 1
Udo Baumgartner, Rögnvaldur G. Möller, George A. Willis
The flat-rank of a totally disconnected, locally compact group G is an integer, which is an invariant of G as a topological group. We generalize the concept of hyperbolic groups to…
Geometric characterization of flat groups of automorphisms
Udo Baumgartner, Günter Schlichting, George A. Willis
If H is a flat group of automorphisms of finite rank n of a totally disconnected, locally compact group G, then each orbit of H in the metric space B(G) of compact, open subgroups…
Hecke algebras from groups acting on trees and HNN extensions
Udo Baumgartner, Marcelo Laca, Jacqui Ramagge +1
We study Hecke algebras of groups acting on trees with respect to geometrically defined subgroups. In particular, we consider Hecke algebras of groups of automorphisms of locally f…
Contraction groups in complete Kac-Moody groups
Udo Baumgartner, Jacqui Ramagge, Bertrand Remy
Let be an abstract Kac-Moody group over a finite field and be the closure of the image of in the automorphism group of its positive building. We show that if the…