Local rigidity of 3-dimensional cone-manifolds

Abstract

We investigate local rigidity of 3-dimensional cone-manifolds with cone-angles not larger than $pi$. Under this cone-angle restriction the singular locus is a trivalent graph. We obtain local rigidity in the hyperbolic and the spherical case. From a technical point of view the main result is a vanishing theorem for $L^2$-cohomology of the smooth part of the cone-manifold with coefficients in the flat vectorbundle of infinitesimal isometries. From this local rigidity is deduced by an analysis of the variety of representations.We investigate local rigidity of 3-dimensional cone-manifolds with cone-angles not larger than $pi$. Under this cone-angle restriction the singular locus is a trivalent graph. We obtain local rigidity in the hyperbolic and the spherical case. From a technical point of view the main result is a vanishing theorem for $L^2$-cohomology of the smooth part of the cone-manifold with coefficients in the flat vectorbundle of infinitesimal isometries. From this local rigidity is deduced by an analysis of the variety of representations