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排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
The problem of nonparametric stationary distribution function estimation by the observations of an ergodic diffusion process is considered. The local asymptotic minimax lower bound on the risk of all the estimators is found and it is proved that the empirical distribution function is asymptotically efficient in the sense of this bound. 相似文献
992.
Ricardo García López 《manuscripta mathematica》1998,97(1):45-58
We give upper bounds for the absolute value of exponential sums in several variables attached to certain polynomials with
coefficients in a finite field. This bounds are given in terms of invariants of the singularities of the projective hypersurface
defined by its highest degree form. For exponential sums attached to the reduction modulo a power of a large prime of a polynomial
f with integer coefficients and veryfying a certain condition on the singularities of its highest degree form, we give a bound
in terms of the dimension of the Jacobian quotient .
Received: 3 November 1997 相似文献
993.
John Hawkes 《Probability Theory and Related Fields》1998,112(1):1-11
Exact results are proved for the capacity of pullbacks of analytic sets by stable processes.
Received: 25 May 1988 / Revised version: 15 September 1997 相似文献
994.
Yurij M. Berezansky 《Integral Equations and Operator Theory》1998,30(2):163-190
A jacobi field is understood to be a family (Ã()) of commuting selfadjoint operatorsÃ() acting in a Fock space, having a Jacobi structure, and depending linearly on the test functions . In this article, we give a spectral representation of such a family and outline its applications to the theory of distributions on an infinite dimensional space.This article is dedicated to the memory of my dear teacher Mark G. KreinThe work is partially supported by Fundamental Research Foundation of Ukraine, grant 1.4/62. 相似文献
995.
Nikolai Yu. Bakaev 《BIT Numerical Mathematics》1998,38(3):462-485
We consider a Cauchy problem for the sectorial evolution equation with generally variable operator in a Banach space. Variable
stepsize discretizations of this problem by means of a strongly A(φ)-stable Runge-Kutta method are studied. The stability
and error estimates of the discrete solutions are derived for wider families of nonuniform grids than quasiuniform ones (in
particular, if the operator in question is constant or Lipschitz-continuous, for arbitrary grids). 相似文献
996.
Meixner polynomials m
n
(x;β,c) form a postive-definite orthogonal system on the positive real line x > 0 with respect to a distribution step function whose jumps are Unlike classical orthogonal polynomials, they do not satisfy a second-order linear differential equation. In this paper,
we derive two infinite asymptotic expansions for m
n
(nα;β,c) as . One holds uniformly for , and the other holds uniformly for , where a and b are two small positive quantities. Both expansions involve the parabolic cylinder function and its derivative. Our results
include all five asymptotic formulas recently given by W. M. Y. Goh as special cases.
April 16, 1996. Date revised: October 30, 1996. 相似文献
997.
Stephan Luckhaus Thomas Sturzenhecker 《Calculus of Variations and Partial Differential Equations》1995,3(2):253-271
In this paper we apply the method of implicit time discretization to the mean curvature flow equation including outer forces. In the framework ofBV-functions we construct discrete solutions iteratively by minimizing a suitable energy-functional in each time step. Employing geometric and variational arguments we show an energy estimate which assures compactness of the discrete solutions. An additional convergence condition excludes a loss of area in the limit. Thus existence of solutions to the continuous problem can be derived. We append a brief discussion of the related Mullins-Sekerka equation.This work was supported by the Deutsche Forschungsgemeinschaft through Sonderforschungsbereich 256, Bonn 相似文献
998.
We introduce a candidate for the group algebra of a Hausdorff group which plays the same role as the group algebra of a finite group. It allows to define a natural bijection betweenk-continuous representations of the group in a Hilbert space and continuous representations of the group algebra. Such bijections are known, but to our knowledge only for locally compact groups. We can establish such a bijection for more general groups, namely Hausdorff groups, because we replace integration techniques by functorial methods, i.e., by using a duality functor which lives in certain categories of topological Banach balls (resp., unit balls of Saks spaces).This paper was written while the authors were supported by the Swiss National Science Foundation under grant 21-33644.92. 相似文献
999.
Mark J. Nielsen 《Geometriae Dedicata》1995,54(3):245-254
We show that given any simple closed curveJ in 2 and any lineL, the curveJ contains the four vertices of some rhombusR with two sides parallel toL. Furthermore, the cyclic order of the vertices ofR agrees with their cyclic order onJ. We also show that the diameters of the rhombi so produced (one for each lineL) may be bounded away from zero. 相似文献
1000.
V. V. Maimeskul 《Constructive Approximation》1995,11(1):1-21
We study the rate of approximation of a functionfA(K) in the interior of the compact setK by polynomials, that are close to best polynomial approximants on the whole setK. Lower and upper estimates of possible improvement of convergence (depending on the geometry ofK) are obtained.Communicated by Vilmos Totik. 相似文献