Xem 1-10 trên 10 kết quả Isometries
  • The goal of this paper is to describe all closed, aspherical Riemannian manifolds M whose universal covers M have a nontrivial amount of symmetry. By this we mean that Isom(M ) is not discrete. By the well-known theorem of Myers-Steenrod [MS], this condition is equivalent to [Isom(M ) : π1 (M )] = ∞. Also note that if any cover of M has a nondiscrete isometry group, then so does its universal cover M . Our description of such M is given in Theorem 1.2 below. The proof of this theorem uses methods from Lie theory, harmonic maps,...

    pdf27p dontetvui 17-01-2013 32 6   Download

  • Tuyển tập các báo cáo nghiên cứu khoa học ngành toán học tạp chí Journal of Operator Theory đề tài: Semigroups isometries với dự đoán phạm vi đi lại...

    pdf36p matuot_266 27-08-2011 26 4   Download

  • Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Research Article Isometries on Products of Composition and Integral Operators on Bloch Type Space

    pdf9p dauphong14 11-02-2012 18 4   Download

  • We show that a finitely presented one-ended group which is not commensurable to a surface group splits over a two-ended group if and only if its Cayley graph is separated by a quasi-line. This shows in particular that splittings over two-ended groups are preserved by quasi-isometries. 0. Introduction Stallings in [St1], [St2] shows that a finitely generated group splits over a finite group if and only if its Cayley graph has more than one end.

    pdf73p noel_noel 17-01-2013 23 3   Download

  • Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Research Article Inequalities in Additive N-isometries on Linear N-normed Banach Spaces

    pdf12p dauphong18 09-03-2012 10 2   Download

  • Let X = G/K be a homogeneous Riemannian manifold where G is the identity component of its isometry group. A C ∞ function F on X is harmonic if it is annihilated by every element of DG (X), the algebra of all G-invariant differential operators without constant term. One of the most beautiful results in the harmonic analysis of symmetric spaces is the Helgason conjecture, which states that on a Riemannian symmetric space of noncompact type, a function is harmonic if and only if it is the Poisson integral of a hyperfunction over the Furstenberg boundary G/Po where...

    pdf59p tuanloccuoi 04-01-2013 26 6   Download

  • We prove the Bers density conjecture for singly degenerate Kleinian surface groups without parabolics. 1. Introduction In this paper we address a conjecture of Bers about singly degenerate Kleinian groups. These are discrete subgroups of PSL2 C that exhibit some unusual behavior: • As groups of projective transformations of the Riemann sphere C they act properly discontinuously on a topological disk whose closure is all of C. • As groups of hyperbolic isometries their action on H3 is not convex cocompact. ...

    pdf18p noel_noel 17-01-2013 22 5   Download

  • There are very few examples of Riemannian manifolds with positive sectional curvature known. In fact in dimensions above 24 all known examples are diffeomorphic to locally rank one symmetric spaces. We give a partial explanation of this phenomenon by showing that a positively curved, simply connected, compact manifold (M, g) is up to homotopy given by a rank one symmetric space, provided that its isometry group Iso(M, g) is large. More precisely we prove first that if dim(Iso(M, g)) ≥ 2 dim(M ) − 6, then M is tangentially homotopically equivalent to a rank one symmetric space or M...

    pdf63p noel_noel 17-01-2013 31 4   Download

  • This intuitive yet rigourous introduction derives the core results of digital communication from first principles. Theory, rather than industry standards, motivates the engineering approaches, and key results are stated with all the required assumptions. The book emphasizes the geometric view, opening with the inner product, the matched filter for its computation, Parseval's theorem, the sampling theorem as an orthonormal expansion, the isometry between passband signals and their baseband representation, and the spectral-efficiency optimality of quadrature amplitude modulation (QAM).

    pdf0p ringphone 06-05-2013 26 4   Download

  • V an isometry, as in the theorem of Plancherel, is not just a weighted L2-norm on some measure space. This is due to the fact that the back transformation Z has a different expression on each branch, and this is caused by the ramification of the domain. It is not clear to us how one could find a family of generalized eigenfunctions leading to a spectral representation of A.

    pdf0p camchuong_1 04-12-2012 18 3   Download


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