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In the present paper, we study an approximation process by a sequence of operators with a prescribed asymptotic behavior. The method of construction of these operators is due to Altomare and Amiar. The operators have several applications in semigroup theory. Our investigation provides an insight in their asymptotic behaviour. Finally, we apply our results to concrete examples of approximation operators recently defined and used by Altomare and Milella for the study of semigroups.  相似文献   

3.
Abstract

Recently, Müller introduced and studied left quasi interpolants of his Gamma operators. In this article we present the complete asymptotic expansion of these operators. As a special case we obtain a Voronovskaja type theorem.  相似文献   

4.
We obtain a complete asymptotic expansion of the integrated density of states of operators of the form ${H = (-\Delta)^w+ B}$ in ${\mathbb{R}^d}$ . Here w >  0 and B belong to a wide class of almost-periodic self-adjoint pseudo-differential operators of order less than 2w. In particular, we obtain such an expansion for magnetic Schrödinger operators with either smooth periodic or generic almost-periodic coefficients.  相似文献   

5.
张春苟 《数学学报》1998,41(6):0-1248
本文给出了高维单纯形上Kantorovich算子在Lp(1<P<∞)范数下的高阶渐近展开公式.  相似文献   

6.
A technique for obtaining asymptotic expansions of integralsby approximating the integrand and then using generalized functiontheory to evaluate the approximated integral is described. Thegeneral technique is presented here by way of a specific example,namely, the expansion of Laplace transforms about the origin.Error bounds for these expansions are also obtained.  相似文献   

7.
《代数通讯》2013,41(9):3581-3608
Abstract

We define generalized Virasoro operators acting on a Fock space V(Γ). These generalize the standard construction of Virasoro operators. By using the Jacobi Identity we compute the commutators of these operators. These operators result in an abelian extension of the toroidal Lie algebra. We explicitly describe the abelian extension.  相似文献   

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In this paper, we prove three strong convergence theorems of modified Mann iteration for relatively asymptotically nonexpansive mappings, relatively nonexpansive mappings, and maximal monotone operators in a Banach space, respectively. Our results extend and improve the recent ones announced by Nakajo, Takahashi, Matsushita, Kim, Martinez-Yanex, Xu, and some others.  相似文献   

10.
The present paper deals with the study of a Durrmeyer-type integral modification of certain modified Baskakov operators. Here we study simultaneous approximation properties for these operators by using the iterative combinations. We obtain an asymptotic formula and an error estimation in terms of higher order modulus of continuity for these operators.   相似文献   

11.
The purpose of this article is to study the local rate of convergence of the Chlodovsky operators (Cnf)(x). As the main results, we investigate their asymptotic behaviour and derive the complete asymptotic expansions of these operators. All the coefficients of n?k (k = 1, 2,…) are calculated in terms of the Stirling numbers of first and second kind. We mention that analogous results for the Bernstein polynomials can be found in Lorentz [2 G. G. Lorentz ( 1953 ). Bernstein Polynomials . University of Toronto Press , Toronto . [Google Scholar]].  相似文献   

12.
Generalized OWA Aggregation Operators   总被引:7,自引:0,他引:7  
We extend the ordered weighted averaging (OWA) operator to a provide a new class of operators called the generalized OWA (GOWA) operators. These operators add to the OWA operator an additional parameter controlling the power to which the argument values are raised. We look at some special cases of these operators. One important case corresponds to the generalized mean and another special case is the ordered weighted geometric operator.  相似文献   

13.
设B(H)表示定义在希尔伯特空间H,上的所有有界线性算子的全体.如果A∈B(H)满足二次算子方程A2=αA βP,其中α,β∈C,P是一个非零的幂等算子且AP=PA=A,则称A为广义二次算子.记L(P)为关于幂等算子P的广义二次算子之集.我们用算子谱论的方法研究了L(P)的谱和群逆等相关性质,并推广了R. W. Farebrother和G. Trenkler的结论.  相似文献   

14.
The Davies problem is connected with the maximal constants in Hardy-type inequalities. We study the generalizations of this problem to the Rellich-type inequalities for polyharmonic operators in domains of the Euclidean space. The estimates are obtained solving the generalized problem under an additional minimal condition on the boundary of the domain. Namely, for a given domain we assume the existence of two balls with sufficiently small radii and the following property: the balls have only a sole common point; one ball lies inside the domain and the other is disjoint from the domain.  相似文献   

15.
We define classes of pseudodifferential operators on G-bundles with compact base and give a generalized L 2 Fredholm theory for invariant operators in these classes in terms of von Neumann’s G-dimension. We combine this formalism with a generalized Paley–Wiener theorem, valid for bundles with unimodular structure groups, to provide solvability criteria for invariant operators. This formalism also gives a basis for a G-index for these operators. We also define and describe a transversal dimension and its corresponding Fredholm theory in terms of anisotropic Sobolev estimates, valid also for similar bundles with nonunimodular structure group.  相似文献   

16.
This paper describes a generalization of the Papert–Papert–Isbell adjunction between topological spaces and frames to a generalized one between the category of generalized topological spaces and the category of complete join-semilattices. Within these categories we aim to study certain separation axioms in a categorical point of view.  相似文献   

17.
非线性算子的渐近歧点   总被引:6,自引:0,他引:6  
利用拓扑度方法作为主要工具研究Banach空间中非线性算子的渐近歧点的存在性,但并没有假定非线性算子是渐近线性算子.最后,把一般结果应用于常微分方程的Sturm-Liouville问题.  相似文献   

18.
In this paper the results from [7, 8], concerning the asymptotic behaviour of the spectral function on the diagonal for Schrodinger operators h →0, are extended to the case of some h-admissible operators, acting in Rn, no 2.  相似文献   

19.
《大学数学》2015,(4):1-8
给出一个递推关系式来确定调和数的渐近展开式的系数.我们建立了Euler-Mascheroni常数的不等式.  相似文献   

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