Coordinates on Schubert cells, Kostant's harmonic forms, and the Bruhat-Poisson structure on G/BWe relate Kostant's theorem on the cohomology of a flag manifold G/B with the geometry of the Bruhat-Poisson structure. We express Kostant's harmonic forms in terms of the moment maps (for…Jiang-Hua Lu·Oct 18, 1996SaveLearn
Transverse measures, the modular class, and a cohomology pairing for Lie algebroidsWe show that every Lie algebroid A over a manifold P has a natural representation on the line bundle QA = topA top T*P. The line bundle QA may be viewed as the…Sam Evens, Jiang-Hua Lu, Alan Weinstein·Oct 16, 1996SaveLearn
De Rham theorem for extended L2-cohomologyWe prove an analogue of the de Rham theorem for the extended L2-cohomology introduced by M. Farber. This is done by establishing that the de Rham complex over a compact closed manifold with…Mikhail Shubin·Oct 11, 1996SaveLearn
Bonnet pairs and isothermic surfacesIn this note we classify all Bonnet pairs on a simply connected domain. Our main intent was to apply what we call a quaternionic function theory to a concrete problem in differential geometry. The…George Kamberov, Franz Pedit, Ulrich Pinkall·Oct 9, 1996SaveLearn
The Spinor Representation of Surfaces in SpaceThe spinor representation is developed for conformal immersions of Riemann surfaces into space. We adapt the approach of Dennis Sullivan, which treats a spin structure on a Riemann surface M as a…Rob Kusner, Nick Schmitt·Oct 8, 1996SaveLearn
Moduli Spaces of Embedded Constant Mean Curvature Surfaces with Few Ends and Special SymmetryWe give necessary conditions on complete embedded surfaces with three or four ends subject to reflection symmetries. The respective submoduli spaces are two-dimensional varieties in the moduli…K. Brauckmann, R. Kusner·Oct 8, 1996SaveLearn
Groups quasi-isometric to symmetric spacesWe determine the structure of finitely generated groups which are quasi-isometric to symmetric spaces of noncompact type, allowing Euclidean de Rham factors If X is a symmetric space of noncompact…Bruce Kleiner, Bernhard Leeb·Oct 6, 1996SaveLearn
Determinant lines, von Neumann algebras and L2 torsionIn this paper, we suggest a construction of determinant lines of finitely generated Hilbertian modules over finite von Neumann algebras. Nonzero elements of the determinant lines can be viewed as…A. Carey, M. Farber, V. Mathai·Oct 3, 1996SaveLearn
Abelian Chern-Simons theoryWe give a construction of the abelian Chern-Simons gauge theory from the point of view of a 2+1 dimensional topological quantum field theory. The definition of the quantum theory relies on geometric…Mihaela Manoliu·Oct 1, 1996SaveLearn
Quantization of symplectic tori in a real polarizationWe apply the geometric quantization method with real polarizations to the quantization of a symplectic torus. By quantizing with half-densities we canonically associate to the symplectic torus a…Mihaela Manoliu·Sep 30, 1996SaveLearn
The spectrum of Kleinian manifoldsA Kleinian manifold Y is a quotient of a rank-one symmetric space of non-compact type by a convex-cocompact discrete group of isometries. We describe the spectral decomposition of the space of square…U. Bunke, M. Olbrich·Sep 30, 1996SaveLearn
On a theorem by do Carmo and DajczerWe give a new proof of a theorem by M.P. do Carmo and M. Dajczer on helicoidal surfaces of constant mean curvature.Guido Haak·Sep 25, 1996SaveLearn
On index formulas for manifolds with metric hornsIn this paper we discuss the index problem for geometric differential operators (Spin-Dirac operator, Gauß-Bonnet operator, Signature operator) on manifolds with metric horns. On singular manifolds…Matthias Lesch, Norbert Peyerimhoff·Sep 24, 1996SaveLearn
Deforming a map into a harmonic mapUsing a flow first introduced by J.P. Anderson, we obtain some existence theorems for harmonic maps from a noncompact complete Riemannian manifold into a complete Riemannian manifold. In particular,…Deane Yang·Sep 21, 1996SaveLearn
Great sphere foliations and manifolds with curvature bounded aboveThe survey is devoted to Toponogov's conjecture, that if a complete simply connected Riemannian manifold with sectional curvature 4 and injectivity radius π/2 has extremal…Vladimir Y. Rovenskii, Victor A. Toponogov·Sep 20, 1996SaveLearn
On constant mean curvature surfaces with periodic metricWe investigate CMC-surfaces with periodic metric in a dressing orbit of the cylinder. It is shown, that such surfaces are always of finite type. Using the periodicity conditions for the extended…Josef Dorfmeister, Guido Haak·Sep 20, 1996SaveLearn
Stiefel-Whitney CurrentsA canonically defined mod 2 linear dependency current is associated to each collection of m sections of a real rank n vector bundle. This current is supported on the linear dependency set of the…Reese Harvey, John Zweck·Sep 17, 1996SaveLearn
Approximating L2 invariants of amenable covering spaces: A combinatorial approachIn this paper, we prove that the L2 Betti numbers of an amenable covering space can be approximated by the average Betti numbers of a regular exhaustion, proving a conjecture that we made in an…Jozef Dodziuk, Varghese Mathai·Sep 16, 1996SaveLearn
Spinors, Nonlinear Connections, and Nearly Autoparallel Maps of Generalized Finsler SpacesWe review the geometric setting of the field theory with locally anisotropic interactions. The concept of locally anisotropic space is introduced as a general one for various type of extensions of…Sergiu I. Vacaru·Sep 16, 1996SaveLearn
Approximating L2 invariants of amenable covering spaces: A heat kernel approachIn this paper, we prove that the L2 Betti numbers of an amenable covering space can be approximated by the average Betti numbers of a regular exhaustion, under some hypotheses. We also prove that…Jozef Dodziuk, Varghese Mathai·Sep 6, 1996SaveLearn
On the eta-invariant of certain nonlocal boundary value problemsMotivated by the work of Vishik on the analytic torsion we introduce a new class of generalized Atiyah-Patodi-Singer boundary value problems. We are able to derive a full heat expansion for this…Jochen Brüning, Matthias Lesch·Sep 4, 1996SaveLearn
Kaehler structures on Kc/(P,P)Let K be a compact semi-simple Lie group. We classify K-invariant Kaehler structures on the space Kc/(P,P), where Kc is the complexification of K, P is a parabolic subgroup of Kc, and (P,P) the…Meng-Kiat Chuah·Aug 28, 1996SaveLearn
Stability of symmetric tops via one variable calculusWe study the stability of symmetric trajectories of a particle on the Lie group SO(3) whose motion is governed by an SO(3)× SO(2) invariant metric and an SO(2)× SO(2) invariant…Eugene Lerman·Aug 28, 1996SaveLearn
A universal lower bound for the first eigenvalue of the Dirac operator on quaternionic Kaehler manifoldsA universal lower bound for the first positive eigenvalue of the Dirac operator on a compact quaternionic Kaehler manifold M of positive scalar curvature is calculated. It is shown that it is equal…Wolfram Kramer·Aug 28, 1996SaveLearn
Discriminants of convex curves are homeomorphicFor a given real generic curve : S1 RPn let D denote the ruled hypersurface in RPn consisting of all osculating subspaces to of codimension 2. A curve $:…B. Shapiro·Aug 26, 1996SaveLearn