{ "id": "1712.05480", "version": "v1", "published": "2017-12-15T00:02:00.000Z", "updated": "2017-12-15T00:02:00.000Z", "title": "Higher horospherical limit sets for G-modules over CAT(0) spaces", "authors": [ "Robert Bieri", "Ross Geoghegan" ], "categories": [ "math.GR" ], "abstract": "The Sigma-invariants of Bieri-Neumann-Strebel and Bieri-Renz involve an action of a discrete group G on a geometrically suitable space M. In the early versions, M was always a finite-dimensional Euclidean space on which G acted by translations. A substantial literature exists on this, connecting the invariants to group theory and to tropical geometry (which, actually, Sigma-theory anticipated). More recently, we have generalized these invariants to the case where M is a proper CAT(0) space on which G acts by isometries. The \"0th stage\" of this was developed in our paper [BG16]. The present paper provides a higher-dimensional extension of the theory to the \"nth stage\" for any n.", "revisions": [ { "version": "v1", "updated": "2017-12-15T00:02:00.000Z" } ], "analyses": { "subjects": [ "20F65", "20E42", "14T05" ], "keywords": [ "higher horospherical limit sets", "finite-dimensional euclidean space", "0th stage", "proper cat", "discrete group" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }