数学学报杂志 北大期刊 CSCD期刊 统计源期刊

A Property of g-Expectation

作者：LongJIANG 刊期：2004年第05期

This paper proves that, under the hypothesis g(t, 0, 0) ≡ 0 and some natural assumptions, the generator g of a backward stochastic differential equation can be uniquely determined by the corresponding g-expectations with all terminal conditions. The main result of this paper also confirms and extends Peng Shige's co...

Littlewood-Paley and Pseudo-Differential Operators on Herz-type Spaces over Vilenkin Groups

作者：YuePingZHU 刊期：2004年第05期

In this paper, we mainly investigate the boundedness of Littlewood-Paley functions and pseudo-differential operators on weighted Herz-type Hardy spaces over locally compact Vilenkin groups.

L^2（R^n） Boundedness for the Commutators of Homogeneous Singular Integral Operators

作者：GuoEnHU; BoLinMA 刊期：2004年第05期

The commutators of singular integral operators with homogeneous kernel Ω(x)/|x|^n are studied, where Ω is homogeneous of degree zero, and has mean value zero on the unit sphere. It is proved that Ω∈ L(logL)^(k+1)(S^(n-1)) is a sufficient condition such that the k-th order commutator is bounded on L^2(R^n).

On the Self-adjointness of the Product Operators of Two ruth-Order Differential Operators on [0, ＋∞）

作者：JianYeAN; JiongSUN 刊期：2004年第05期

In the present paper, the self-adjointness of the product of two mth-order differential operators on [0, ∞) is studied. By means of the construction theory of self-adjoint operators and matrix computation, we obtain a sufficient and necessary condition to ensure that the product operator is self-adjoint, which exten...

Upper Bounds for the Laplacian Graph Eigenvalues

作者：JiongShengLI; YongLiangPAN 刊期：2004年第05期

We first apply non-negative matrix theory to the matrix K = D + A, where D and A are the degree-diagonal and adjacency matrices of a graph G, respectively, to establish a relation on the largest Laplacian eigenvalue λ1 (G) of G and the spectral radius p(K) of K. And then by using this relation we present two upper bo...

Linear Maps Preserving Idempotence on Nest Algebras

作者：JianLianCUI; JinChuanHOU 刊期：2004年第05期

In this paper, we discuss the rank-l-preserving linear maps on nest algebras of Hilbertspace operators. We obtain several characterizations of such linear maps and apply them to show that a weakly continuous linear hijection on an atomic nest algebra is idempotent preserving if and only if it is a Jordan homomorphism...

Stability of C-regularized Semigroups

作者：MiaoLI; QuanZHENG 刊期：2004年第05期

Let T = (T(t))t≥0 be a bounded C-regularized semigroup generated by A on a Banach space X and R(C) be dense in X. We show that if there is a dense subspace Y of X such that for every x ∈ Y, σu(A, Cx), the set of all points λ ∈ iR to which (λ - A)^-1 Cx can not be extended holomorphically, is at most countable and ...

Non-expansive Mappings and Iterative Methods in Uniformly Convex Banach Spaces

作者：Ha|YunZHOU 刊期：2004年第05期

In this article, we will investigate the properties of iterative sequence for non-expansive mappings and present several strong and weak convergence results of successive approximations to fixed points of non-expansive mappings in uniformly convex Banach spaces. The results presented in this article generalize and im...

On Pairs of Linear Equations in Three Prime Variables

作者：HongZeLI; RichardJ.MCINTOSH 刊期：2004年第05期

In this paper, we consider the simultaneous representation of pairs of integers as linear combinations in three prime variables and obtain a related numerical bound.

An Application of Exponential Sum Estimates

作者：YuanYI; WenPengZHANG 刊期：2004年第05期

A Decomposition Theorem for the Solutions to the Interface Problems of Quasi-Linear Elliptic Equations

作者：LungAnYING 刊期：2004年第05期

Interface problems for second order quasi-linear elliptic partial differential equations in a two-dimensional space are studied. We prove that each weak solution can be decomposed into two parts near singular points, one of which is a finite sum of functions of the form cr^a log^m rφ(θ), where the coefficients c depe...

Almost Sure Central Limit Theorems for Heavily Trimmed Sums

作者：FangWANG; ShiHongCHENG 刊期：2004年第05期

We obtain an almost sure central limit theorem (ASCLT) for heavily trimmed sums. We also prove a function-typed ASCLT under the same conditions that assure measurable functions to satisfy the ASCLT for the partial sums of i.i.d, random variables with E X1 = 0, EX1^2 = 1.

Wavelets and Wavelet Packets Related to a Class of Dilation Matrices

作者：QiaoFangLIAN 刊期：2004年第05期

The construction of wavelets generated from an orthogonal multiresolution analysis can be reduced to the unitary extension of a matrix, which is not easy in most cases. Jia and Micchelli gave a solution to the problem in the case where the dilation matrix is 21 and the dimension does not exceed 3. In this paper, by t...

Torsion Completeness of Sylow p-Groups in Semisimple Group Rings

作者：P.V.DANCHEV 刊期：2004年第05期

Let G be an abelian p-group and K be a field of the first kind with respect to p of char K ≠p and of sp(K) = N or NU {0}. Then it is shown that the normed Sylow p-subgroup S(KG) is torsion complete if and only if G is bounded (Theorem 1). An analogous fact is proved for the case when K is of the second kind (Theorem...

Smooth Solution to the 1-Dimensional Spin Equations of Antiferromagnets

作者：ShiJinDING; BoLingGUO 刊期：2004年第05期

In this paper, the global existence and uniqueness of a smooth solution to the periodic initial-value problem of the spin equations of antiferromagnets in 1 dimension are proved.