2014/07/15 by Matthias Keller, Keller, Matthias, Norbert Peyerimhoff +3
Mathematics · #FOS: Mathematics #Group Theory (math.GR) #Metric Geometry (math.MG) #Spectral Theory (math.SP) #math.GR #math.MG #math.SP
paper · pdf · doi:10.48550/arxiv.1407.4024
32 pages, 3 figures
arxiv created 2014/07/15 · arxiv updated 2014/07/16
In this paper we introduce a class of polygonal complexes for which we can define a notion of sectional combinatorial curvature. These complexes can be viewed as generalizations of 2-dimensional Euclidean and hyperbolic buildings. We focus on the case of non-positive and negative combinatorial curvature. As geometric results we obtain a Hadamard-Cartan type theorem, thinness of bigons, Gromov hyperbolicity and estimates for the Cheeger constant. We employ the latter to get spectral estimates, show discreteness of the spectrum in the sense of a Donnelly-Li type theorem and present corresponding eigenvalue asymptotics. Moreover, we prove a unique continuation theorem for eigenfunctions and the solvability of the Dirichlet problem at infinity.