362 research outputs found

    The best constant of the discrete Sobolev inequalities on the complete bipartite graph

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    We have the best constants of three kinds of discrete Sobolev inequalities on the complete bipartite graph with 2N vertices, that is, KN,N. We introduce a discrete Laplacian A on KN,N. A is a 2N ×2N real symmetric positive-semidefinite matrix whose eigenvector corresponding to zero eigenvalue is 1 = t(1, 1, … , 1)∈ C2N. A discrete heat kernel, a Green’s matrix and a pseudo Green’s matrix play important roles in giving the best constants

    THE BEST CONSTANT OF L<sup>p</sup> SOBOLEV INEQUALITY CORRESPONDING TO DIRICHLET-NEUMANN BOUNDARY VALUE PROBLEM

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    We have obtained the best constant of the following Lp Sobolev inequality sup 0≤y≤1| u(j)(y)| ≤C (∫ 01 | u(M)(x)| p dx)1/p , where u is a function satisfying u(M) ∈ Lp(0, 1), u(2i)(0) = 0 (0 ≤i ≤ [(M − 1)/2]) and u(2i+1)(1) = 0 (0 ≤ i ≤ [(M − 2)/2]), where u(i) is the abbreviation of (d/dx)iu(x). In [9], the best constant of the above inequality was obtained for the case of p = 2 and j = 0. This paper extends the result of [9] under the conditions p > 1 and 0 ≤ j ≤ M −1. The best constant is expressed by Bernoulli polynomials

    Positivity and Hierarchical Structure of four Green Functions Corresponding to a Bending Problem of a Beam on a half line

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    We consider the boundary value problem for fourth order linear ordinary differential equation in a half line (0,∞), which represents bending of a beam on an elastic foundation under a tension. A tension is relatively stronger than a spring constant of elastic foundation. We here treat four self-adjoint boundary conditions, clamped, Dirichlet, Neumann and free edges, at x = 0. We show the positivity and the hierarchical structure of four Green functions

    Complete Caudate Lobectomy: Its Definition, Indications, and Surgical Approaches

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    There are three ways to approach and resect the caudate lobe of the liver, that is; and isolated caudate lobectomy, a combined resection of the liver overlying the caudate lobe, and a transhepatic anterior approach by splitting parenchyma of the liver

    Minimally Invasive Spinal Stabilization with Denosumab before Total Spondylectomy for a Collapsing Lower Lumbar Spinal Giant Cell Tumor

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    A 21-year-old man consulted our hospital for treatment of a spinal giant cell tumor (GCT) of Enneking stage III. Lower lumbar-spine tumors and severe spinal canal stenosis are associated with high risk for surgical mor-bidity. Stability was temporarily secured with a percutaneous pedicle screw fixation in combination with deno-sumab, which shrank the tumor. Total en bloc spondylectomy was then performed 6 months after initiation of denosumab, and the patient was followed for 3 years. There was no local recurrence, and bony fusion was obtained. Minimally invasive surgery and denosumab allowed safer and easier treatment of a collapsing lower lumbar extra-compartmental GCT
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