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911.
Mark Grant 《Topology and its Applications》2012,159(1):88-97
We show how locally smooth actions of compact Lie groups on a manifold X can be used to obtain new upper bounds for the topological complexity TC(X), in the sense of Farber. We also obtain new bounds for the topological complexity of finitely generated torsion-free nilpotent groups. 相似文献
912.
Matteo Tommasini 《Topology and its Applications》2012,159(3):756-786
We define a 2-category structure (Pre-Orb) on the category of reduced complex orbifold atlases. We construct a 2-functor F from (Pre-Orb) to the 2-category (Grp) of proper étale effective groupoid objects over the complex manifolds. Both on (Pre-Orb) and (Grp) there are natural equivalence relations on objects: (a natural extension of) equivalence of orbifold atlases on (Pre-Orb) and Morita equivalence in (Grp). We prove that F induces a bijection between the equivalence classes of its source and target. 相似文献
913.
We introduce the notion of a partial geometric difference family as a variation on the classical difference family and a generalization of partial geometric difference sets. We study the relationship between partial geometric difference families and both partial geometric designs and difference families, and show that partial geometric difference families give rise to partial geometric designs. We construct several infinite families of partial geometric difference families using Galois rings and the cyclotomy of Galois fields. From these partial geometric difference families, we generate a list of infinite families of partial geometric designs and directed strongly regular graphs. 相似文献
914.
In this article, a new canonical function has been established to deal with Riemann boundary‐value problem of periodic analytic functions discussed in 16 . In comparison with the corresponding result in 16 , the expression of solution obtained here is much simpler. Then, we demonstrate the equivalence of solutions for the homogeneous Riemann problem. What's more, we obtain the precise rank of matrix of coefficients for the system of linear algebraic equations (4.35) in 16 . Those results can simplify the discussion of Riemann problem of single‐periodic polyanalytic functions in 16 . 相似文献
915.
Global existence and nonexistence of solutions for a viscoelastic wave equation with nonlinear boundary source term 下载免费PDF全文
In this paper, we consider the initial boundary value problem for a viscoelastic wave equation with nonlinear boundary source term. First of all, we introduce a family of potential wells and prove the invariance of some sets. Then we establish the existence and nonexistence of global weak solution with small initial energy under suitable assumptions on the relaxation function , nonlinear function , the initial data and the parameters in the equation. Furthermore, we obtain the global existence of weak solution for the problem with critical initial conditions and . 相似文献
916.
By incorporating the Monotone Upwind Scheme of Conservation Law (MUSCL) scheme into the smoothed particles hydrodynamics (SPH) method and making use of an interparticle contact algorithm, we present a MUSCL–SPH scheme of second order for multifluid computations, which extends the Riemann‐solved‐based SPH method. The numerical tests demonstrate high accuracy and resolution of the scheme for both shocks, contact discontinuities, and rarefaction waves in the one‐dimensional shock tube problem. For the two‐dimensional cylindrical Noh and shock‐bubble interaction problems, the MUSCL–SPH scheme can resolve shocks well. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
917.
Lois Mansfield 《Numerische Mathematik》1984,45(2):165-172
Summary Optimal rates of convergence for the approximate solution of the stationary Stokes equations are obtained for finite element schemes which use piecewise constants to approximate the pressure and piecewise linear or piecewise bilinear or trilinear polynomials to approximate the velocity over fairly general quadrilateral or hexahedral meshes.This research was supported by NSF Grant MC80-16532 相似文献
918.
Shun-Ichi Kimura 《Inventiones Mathematicae》1999,137(3):575-611
Vistoli defined Alexander schemes in [19], which behave like smooth varieties from the viewpoint of intersection theory with
Q-coefficients. In this paper, we will affirmatively answer Vistoli’s conjecture that Alexander property is Zariski local.
The main tool is the abelian category of bivariant sheaves, and we will spend most of our time for proving basic properties
of this category. We show that a scheme is Alexander if and only if all the first cohomology groups of bivariant sheaves vanish,
which is an analogy of Serre’s theorem, which says that a scheme is affine if and only if all the first cohomology groups
of quasi-coherent sheaves vanish. Serre’s theorem implies that the union of affine closed subschemes is again affine. Mimicking
the proof line by line, we will prove that the union of Alexander open subschemes is again Alexander.
Oblatum 1-XII-1997 & 14-XII-1998 / Published online: 10 May 1999 相似文献
919.
Paola Supino 《Mathematische Zeitschrift》1999,231(3):489-516
920.
B. Anchouche 《manuscripta mathematica》1999,100(4):423-436
We show that over some smooth projective varieties every semistable Higgs logarithmic vector bundle is semistable in the ordinary
sense, hence satisfies Bogomolov inequality. More generaly, we prove that semistable Higgs parabolic vector bundles of rank
two over smooth projective varieties of dimension ≥ 2 satisfy the “parabolic” 'Bogomolov inequality
Received: 1 March 1999 / Revised version: 11 June 1999 相似文献