{ "id": "math/0507301", "version": "v1", "published": "2005-07-14T20:27:11.000Z", "updated": "2005-07-14T20:27:11.000Z", "title": "The Large Scale Geometry of Nilpotent-by-Cyclic Groups", "authors": [ "Ashley Reiter Ahlin" ], "comment": "Ph.D. dissertation at University of Chicago Mathematics Department, June 2002", "categories": [ "math.GR", "math.GT" ], "abstract": "A nonpolycyclic nilpotent-by-cyclic group Gamma can be expressed as the HNN extension of a finitely-generated nilpotent group N. The first main result is that quasi-isometric nilpotent-by-cyclic groups are HNN extensions of quasi-isometric nilpotent groups. The nonsurjective injection defining such an extension induces an injective endomorphism phi of the Lie algebra g associated to the Lie group in which N is a lattice. A normal form for automorphisms of nilpotent Lie algebras--permuted absolute Jordan form-- is defined and conjectured to be a quasi-isometry invariant. We show that if phi, theta are endomorphisms of lattices in a fixed Carnot group G, and if the induced automorphisms of g have the same permuted absolute Jordan form, then Gamma_phi and Gamma_theta are quasi-isometric. Two quasi-isometry invariants are also found: the set of ``divergence rates'' of vertical flow lines: D_phi the ``growth spaces'': g_n subset g These do not establish that permuted absolute Jordan form is a quasi-isometry invariant, although they are major steps toward that conjecture. Furthermore, the quasi-isometric rigidity of finitely-presented nilpotent-by-cyclic groups is proven: any finitely-presented group quasi-isometric to a nonpolycyclic nilpotent-by-cyclic group is (virtually-nilpotent)-by-cyclic.", "revisions": [ { "version": "v1", "updated": "2005-07-14T20:27:11.000Z" } ], "analyses": { "keywords": [ "large scale geometry", "permuted absolute jordan form", "lie algebras-permuted absolute jordan", "quasi-isometry invariant", "quasi-isometric" ], "tags": [ "dissertation" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2005math......7301R" } } }