共查询到20条相似文献,搜索用时 15 毫秒
1.
Y. Endow 《Stochastic Processes and their Applications》1985,20(1):157-167
This paper deals with a Walsh-harmonizable dyadic stationary sequence {X(k): k=0, 1, 2,…} which is represented as , where ψk(λ) is the k-th Walsh function and ζ(λ) is a second-order process with orthogonal increments. One of the aims is to express the process {ζ(λ): λ?[0, 1)} in terms of the Walsh–Stieltjes series ∑ X(k)ψk(λ) of the original sequence X(k). In order to do this a Littlewood's Tauberian theorem for a series of random variables is introduced. A finite Walsh series expression of X(k) is derived by introducing an approximate Walsh series of X(k). Also derived is a strong law of large numbers for the dyadic stationary sequences. 相似文献
2.
T. Kilgore 《Periodica Mathematica Hungarica》1996,33(3):175-184
Using the correspondence x↔ cos θ, where −1≤x ≤ 1 and 0 ≤ θ ≤ π, a function f(x) defined on [−1, 1] can be represented as a 2π-periodic function F(θ), and then the derivative f′(x) corresponds to
. From these observations, weighted-norm estimates for first and higher derivatives by x will be obtained, using a generalized Hardy inequality. The results in turn imply the generalized Hardy inequality upon which
they depend and will hold true in any weighted norm for which the generalized Hardy is true. 相似文献
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Robert S. Strichartz 《Journal of Fourier Analysis and Applications》2000,6(5):533-536
The arclengths of the graphs Γ(sN(f)) of the partial sums sN(f) of the Fourier series of a piecewise smooth function f with a jump discontinuity grow at the rate O(logN). This problem does not arise if f is continuous, and can be removed by using the standard summability methods. 相似文献
6.
E. S. Belinskii E. R. Liflyand R. M. Trigub 《Journal of Fourier Analysis and Applications》1997,3(2):103-129
Beurling’s algebra
is considered. A* arises quite naturally in problems of summability of the Fourier series at Lebesgue points, whereas Wiener’s
algebra A of functions with absolutely convergent Fourier series arises when studying the norm convergence of linear means.
Certainly, both algebras are used in some other areas. A* has many properties similar to those of A, but there are certain
essential distinctions. A* is a regular Banach algebra, its space of maximal ideals coincides with[−π, π], and its dual space is indicated. Analogs of Herz’s and Wiener-Ditkin’s theorems hold. Quantitative parameters in an analog
of the Beurling-Pollard theorem differ from those for A. Several inclusion results comparing the algebra A* with certain Banach
spaces of smooth functions are given. Some special properties of the analogous space for Fourier transforms on the real axis
are presented. The paper ends with a summary of some open problems. 相似文献
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J. M. Wills 《Periodica Mathematica Hungarica》1991,22(3):139-146
We consider finite packings of unit-balls in Euclidean 3-spaceE
3 where the centres of the balls are the lattice points of a lattice polyhedronP of a given latticeL
3E3. In particular we show that the facets ofP induced by densest sublattices ofL
3 are not too close to the next parallel layers of centres of balls. We further show that the Dirichlet-Voronoi-cells are comparatively small in this direction. The paper was stimulated by the fact that real crystals in general grow slowly in the directions normal to these dense facets.The results support, to some extent, the hypothesis that real crystals grow preferably such that they need little volume, i.e that they are locally dense.Dedicated to A. Florian on the occasion of this 60th birthday 相似文献
10.
Fei-Tsen Liang 《Annali dell'Universita di Ferrara》2002,48(1):189-217
We consider the problem of determining the existence of absolute apriori gradient bounds of nonparametric hypersurfaces of
constant mean curvature in ann-dimensional sphereB
R, 1>R>R
0
(n)
, (R
0
(n)
being a constant depending only onn), without imposing boundary conditions or bounds of any sort.
Sunto Consideriamo il problema di determinare stime a priori di gradienti di ipersuperfici non parametriche di curvatura media costante in una sferan-dimensionaleB R, 1>R>R 0 (n), (R 0 (n) essendo una costante che dipende solo dan), senza imporre condizioni al contorno o limiti di altro tipo.相似文献
11.
Fang Jia 《Differential Geometry and its Applications》2005,22(2):199-214
Let be a locally strongly convex hypersurface, given by a strictly convex function xn+1=f(x1,…,xn) defined in a convex domain Ω⊂An. We consider the Riemannian metric G# on M, defined by . In this paper we prove that if M is a locally strongly convex surface with constant affine mean curvature and if M is complete with respect to the metric G#, then M must be an elliptic paraboloid. 相似文献
12.
A. G. Miamee 《Periodica Mathematica Hungarica》1993,26(2):115-124
Let be a nonnegative measure on the unit circle in the complex plane and 1<p<. It is of interest to find conditions on so that the set of exponentialse
in
form a strongM-basis forL
p
(d). Some partial results are proved which can shed some light on this important open question. These results are of fundamental importance in the prediction theory of stochastic processes and other fields of applications. These results is then used to obtain a theorem which reduces some prediction problems to easier ones.To 80th birthday of Paul ErdsThis research is supported by Office of Naval Research Grant No N00014-89-J-1824. 相似文献
13.
A. K. Goyal 《Periodica Mathematica Hungarica》1986,17(1):13-20
In this paper,D-strong and almostD-strong near-rings have been defined. It has been proved that ifR is aD-strongS-near ring, then prime ideals, strictly prime ideals and completely prime ideals coincide. Also ifR is aD-strong near-ring with identity, then every maximal right ideal becomes a maximal ideal and moreover every 2-primitive near-ring becomes a near-field. Several properties, chain conditions and structure theorems have also been discussed.Most of the parts of this paper are included in author's doctoral dissertation at Sukhadia University Udaipur (1983). The author expresses his gratitude to Dr.S. C. Choudhary for his kind guidance. 相似文献
14.
Here we present some distribution function inequalities between certain functionals defined relative to a convolution approximation procedure. Such inequalities are best known when the approximation is made using dilations of the Gaussian or Cauchy kernels. In these cases, classical differential equations, the heat equation or Laplace's equation, provide the basis for comparisons; in the latter case, the quadratic functional is known as the Lusin area integral. The kernels we consider are compactly supported, and satisfy a dilation equation, rather than a differential equation. For these kernels, there is an intrinsic quadratic variation, defined from the dilation structure. We obtain good lambda distribution function inequalities between a maximal function and the quadratic variation functional. 相似文献
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Hypersurfaces with constant scalar curvature in space forms 总被引:17,自引:0,他引:17
Li Haizhong 《Mathematische Annalen》1996,305(1):665-672
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This paper develops a general abstract non-holomorphic operator calculus under minimal regularity requirements on the family of operators through the concept of algebraic eigenvalue and the use of a, very recent, transversalization theory. Further, it analyzes under what conditions the inverse of a non-analytic family admits a finite Laurent development, and employs the new findings to calculate the multiplicity of a real non-analytic family through a logarithmic residue, so extending the applicability of the classical theory of I. C. Gohberg and coworkers. Applications to matrix families and Nonlinear Analysis are also explained. 相似文献
19.
We consider a selfadjoint and smooth enough operator-valued functionL() on the segment [a, b]. LetL(a)0,L(b)0, and there exist two positive numbers and such that the inequality |(L()f, f)|< ([a, b] f=1) implies the inequality (L'()f, f)>. Then the functionL() admits a factorizationL()=M()(I-Z) whereM() is a continuous and invertible on [a, b] operator-valued function, and operatorZ is similar to a selfadjoint one. This result was obtained in the first part of the present paper [10] under a stronge conditionL()0 ( [a,b]). For analytic functionL() the result of this paper was obtained in [13]. 相似文献
20.
Ilya Krupnik Alexander Markus Vladimir Matsaev 《Integral Equations and Operator Theory》1993,17(4):554-566
In the present paper we discuss two problems on factorizations of matrix-valued functions with respect to a simple closed rectifiable curve . These two problems are related and we show that in both of them circular contours play a remarkable role. 相似文献