 

Guyan Robertson
Tiling systems and homology of lattices in tree products


Published: 
December 14, 2005

Keywords: 
tree products, lattices, homology, Ktheory, operator algebra 
Subject: 
22E40, 22D25 


Abstract
Let Γ be a torsionfree cocompact lattice in Aut(T_{1}) × Aut(T_{2}),
where T_{1}, T_{2} are trees whose vertices all have degree at least three.
The group H_{2}(Γ, Z) is determined explicitly in terms of an associated
2dimensional tiling system.
It follows that under appropriate conditions the crossed product C*algebra A associated with the action of Γ on the boundary of T_{1}×T_{2} satisfies rank K_{0}(A) = 2⋅rank H_{2}(Γ, Z).


Author information
School of Mathematics and Statistics, University of Newcastle, NE1 7RU, U.K.
a.g.robertson@newcastle.ac.uk

