2005

最新文章

• On the stability of Riemannian manifold with parallel spinors AI翻译
  作者：Dai, XZ; Wang, XD; Wei, GF
  作者单位：University of California System; University of California Santa Barbara; Massachusetts Institute of Technology (MIT)
  摘要：Inspired by the recent work [HHM03], we prove two stability results for compact Riemannian manifolds with nonzero parallel spinors. Our first result says that Ricci flat metrics which also admit nonzero parallel spinors are stable (in the direction of changes in conformal structures) as the critical points of the total scalar curvature functional. Our second result, which is a local version of the first one, shows that any metric of positive scalar curvature cannot lie too close to a metric wi...
• Dynamical entropy in Banach spaces AI翻译
  作者：Kerr, D; Li, HF
  作者单位：Texas A&M University System; Texas A&M University College Station; University of Tokyo; University of Toronto
  摘要：We introduce a version of Voiculescu-Brown approximation entropy for isometric automorphisms of Banach spaces and develop within this framework the connection between dynamics and the local theory of Banach spaces as discovered by Glasner and Weiss. Our fundamental result concerning this contractive approximation entropy, or CA entropy, characterizes the occurrence of positive values both geometrically and topologically. This leads to various applications; for example, we obtain a geometric de...
• Embedding of the operator space OH and the logarithmic 'little Grothendieck inequality' AI翻译
  作者：Junge, M
  作者单位：University of Illinois System; University of Illinois Urbana-Champaign
  摘要：We use Voiculescu's concept of free probability to construct a completely isomorphic embedding of the operator space OH in the predual of a von Neumann algebra. We analyze the properties of this embedding and determine the operator space projection constant of OHn: 108(1) root 1 + ln(n) n (<=) P: B(l(2)) --> OHninf, P-2 = P parallel to P parallel to(cb) <= 288 pi root 1 + ln(2n) n. The lower estimate is a recent result of Pisier and Shlyakhtenko that improves an estimate of order 1/(1+ ln n) o...
• Kupka-Smale theorem for polynomial automorphisms of C2 and persistence of heteroclinic intersections AI翻译
  作者：Buzzard, GT; Hruska, SL; Ilyashenko, Y
  作者单位：Purdue University System; Purdue University; Cornell University; Lomonosov Moscow State University; Russian Academy of Sciences; Steklov Mathematical Institute of the Russian Academy of Sciences; Russian Academy of Sciences; Steklov Mathematical Institute of the Russian Academy of Sciences
  摘要：A map is Kupka-Smale if all periodic points are hyperbolic and the stable and unstable manifolds of any two saddle points are transverse. Here we prove that Kupka-Smale maps form a residual set of full Lebesgue measure in the space P-d of polynomial automorphisms of C-2 of fixed dynamical degree d >= 2. We also prove that a heteroclinic point of two saddle periodic orbits may be continued over (almost) the entire parameter space for this set of maps. This is one of the first persistence theore...
• Answers to some equisingularity questions AI翻译
  作者：de Bobadilla, JF
  作者单位：Utrecht University
  摘要：We give examples of families of hypersurface singularities with constant Le numbers, constant Milnor fibration and non-constant topological type, answering negatively a question of D. Massey. On the other hand we prove that the constancy of the Le numbers implies that the homotopy type of the link is constant along the family. As an application we give an example of a flat family of projective reduced and irreducible hypersurfaces having the same homotopy type but different topological type. A...
• On the ramification of Hecke algebras at Eisenstein primes AI翻译
  作者：Calegari, F; Emerton, M
  作者单位：Harvard University; Northwestern University
• Measures of linear independance of logarithms in a commutative algebraic group AI翻译
  作者：Gaudron, É
  作者单位：Communaute Universite Grenoble Alpes; Universite Grenoble Alpes (UGA); Centre National de la Recherche Scientifique (CNRS); CNRS - National Institute for Mathematical Sciences (INSMI)
  摘要：This work falls within the theory of linear forms in logarithms over a connected and commutative algebraic group, defined over the field of algebraic numbers (Q) over bar. Let G be such a group. Let W be a hyperplane of the tangent space at the origin of G, defined over (Q) over bar, and u be a complex point of this tangent space, such that the image of u by the exponential map of the Lie group G(C) is an algebraic point. Then we obtain a lower bound for the distance between u and W circle tim...
• The motivic fundamental group of P1\{0,1,∞} and the theorem of Siegel AI翻译
  作者：Kim, M
  作者单位：University of Arizona
• Non-minimal scalar-flat Kahler surfaces and parabolic stability AI翻译
  作者：Rollin, Y; Singer, M
  作者单位：Massachusetts Institute of Technology (MIT)
  摘要：A new construction is presented of scalar-flat Kahler metrics on non-minimal ruled surfaces. The method is based on the resolution of singularities of orbifold ruled surfaces which are closely related to rank-2 parabolically stable holomorphic bundles. This rather general construction is shown also to give new examples of low genus: in particular, it is shown that CP2 blown up at 10 suitably chosen points, admits a scalar-flat Kahler metric; this answers a question raised by Claude LeBrun in 1...
• The Plancherel decomposition for a reductive symmetric space - II. Representation theory AI翻译
  作者：van den Ban, EP; Schlichtkrull, H
  作者单位：Utrecht University; Aarhus University; University of Copenhagen
  摘要：We obtain the Plancherel decomposition for a reductive symmetric space in the sense of representation theory. Our starting point is the Plancherel formula for spherical Schwartz functions, obtained in part I. The formula for Schwartz functions involves Eisenstein integrals obtained by a residual calculus. In the present paper we identify these integrals as matrix coefficients of the generalized principal series.