SPHERICAL SYMMETRIC SOLUTIONS FOR THE MOTION OF RELATIVISTIC MEMBRANES AND NULL MEMBRANES IN THE REISSNER-NORDSTROM SPACE-TIME

In this article, we concern the motion of relativistic membranes and null mem- branes in the Reissner-Nordstrom space-time. The equation of relativistic membranes moving in the Reissner-Nordstrom space-time is derived and some properties are discussed. Spherical symmetric solutions for the motion are illustrated and some interesting physical phenomena are discovered. The equations of the null membranes are derived and the exact solutions are also given. Spherical symmetric solutions for null membranes are just the two horizons of Reissner-NordstrSm space-time.     

Normed BCI-algebras

The notions of norm and distance in BCI-algebras are introduced, and some basic properties in normed BCI-algebras are given. It is obtained that the isomorphic（homomorphic） image and inverse image of a normed BCI-algebra are still normed BCI-algebras. The relations of normaled properties between BCI-algebra and Cartesian product of BCIalgebras are investigated. The limit notion of sequence of points in normed BCI-algebras is introduced, and its related properties are investigated.     

Fuzzy dot ideals and fuzzy dot H-ideals of BCH-algebras

The notions of fuzzy dot ideals and fuzzy dot H-ideals in BCH-algebras are introduced, several appropriate examples are provided, and their some properties are investigated. The relations among fuzzy ideal, fuzzy H-ideal, fuzzy dot ideal and fuzzy dot H-ideals in BCH- algebras are discussed, several equivalent depictions of fuzzy dot ideal are obtained. How to deal with the homomorphic image and inverse image of fuzzy dot ideals （fuzzy dot H-ideals） are studied. The relations between a fuzzy dot ideal （fuzzy dot H-ideal） in BCH-algebras and a fuzzy dot ideal （fuzzy dot H-ideal） in the product algebra of BCH-algebras are given.     

SUPERFLUOUS AND S-ESSENTIAL HOMOMORPHISMS

Let R be a ring and S a class of R-modules. S-superfluous epimorphisms and S-essential monomorphisms are introduced and studied in this article. As applications, some new characterizations of von Neumann regular rings and perfect rings are given. Finally, these notions are also used to study minimal homomorphisms.     

ASYMPTOTIC STABILITY OF SINGULAR NONLINEAR DIFFERENTIAL SYSTEMS WITH UNBOUNDED DELAYS

In this paper,the asymptotic stability of singular nonlinear differential systems with unbounded delays is considered.The stability criteria are derived based on a kind of Lyapunov-functional and some technique of matrix inequalities.The criteria are described as matrix equation and matrix inequalities,which are computationally flexible and efficient.Two examples are given to illustrate the results.     

On the rotating Navier-Stokes equations with mixed boundary conditions

The stationary and nonstationary rotating Navier-Stokes equations with mixed boundary conditions are investigated in this paper. The existence and uniqueness of the solutions are obtained by the Galerkin approximation method. Next, θ-scheme of operator splitting algorithm is applied to rotating Navier-Stokes equations and two subproblems are derived. Finally, the computational algorithms for these subproblems are provided.     

Sensitivity analysis of semi-simple eigenvalues of regular quadratic eigenvalue problems

This paper discusses the sensitivity analysis of semisimple eigenvalues and associated eigen-matrix triples of regular quadratic eigenvalue problems analytically dependent on several parameters. The directional derivatives of semisimple eigenvalues are obtained. The average of semisimple eigenvalues and corresponding eigen-matrix triple are proved to be analytic, and their partial derivatives are given. On these grounds, the sensitivities of the semisimple eigenvalues and corresponding eigenvector matrices are defined.     

Finite-Difference Methods for a Class of Strongly Nonlinear Singular Perturbation Problems

The paper is concerned with strongly nonlinear singularly perturbed bound- ary value problems in one dimension.The problems are solved numerically by finite- difference schemes on special meshes which are dense in the boundary layers.The Bakhvalov mesh and a special piecewise equidistant mesh are analyzed.For the central scheme,error estimates are derived in a discrete L~1 norm.They are of second order and decrease together with the perturbation parameterε.The fourth-order Numerov scheme and the Shishkin mesh are also tested numerically.Numerical results showε-uniform pointwise convergence on the Bakhvalov and Shishkin meshes.     

关于矩阵Γα-群逆和Γα序

The Γα-group inverse and the Γα-sharp ordering in matrix set are introduced.Some characterizations and properties of the Γα-sharp ordering are given.The relations between the Γα-sharp ordering and the Γα-mantis ordering are discussed.     

Function P-sets and Mining-discovery Theorems of Unknown Information Law

Function P-sets are a set pair which are composed of function internal packetsets S F and function outer packet sets S F or （S F , S F ） are function P-sets. Function P-sets have dynamic characteristics and law characteristics. Based on function P-sets, P-information law discovery theorems which has attribute supplementing-deleting are given. Mining-discovery and mining-discovery theorems of unknown information law are proposed. Function P-sets are a new theory and new method to research dynamic information laws for information systems.     

Generalization for Amann's and Leggett-Williams' three-solution theorems and applications

In this paper, some new three-solution theorems are obtained. Moreover, the famous Amann's and Leggett-Williams' three-solution theorems in nonlinear functional analysis can be seen as their special cases, namely these two famous theorems are united. So they are both improved. And that some new three-solution theorems are applied to ordinary differential equations, and some new existence results are obtained.     

关于(余)反射的等价性和可扩张性及其应用

该文研究了（余）反射的等价性和可扩张性及应用，得到的主要结果如下：(1) 余反射余代数范畴和反射代数范畴是等价的．(2) 反射和余反射都具有可扩张性．使用这些结果可以用来推广和化简［1-4］中部分结论     

Duality in mathematics and linear and integer programming

Linear programming (LP) duality is examined in the context of other dualities in mathematics. The mathematical and economic properties of LP duality are discussed and its uses are considered. These mathematical and economic properties are then examined in relation to possible integer programming (IP) dualities. A number of possible IP duals are considered in this light and shown to capture some but not all desirable properties. It is shown that inherent in IP models are inequality and congruence constraints, both of which give on their own well-defined duals. However, taken together, no totally satisfactory dual emerges. The superadditive dual based on the Gomory and Chvátal functions is then described, and its properties are contrasted with LP duals and other IP duals. Finally, possible practical uses of IP duals are considered.The author is indebted to Professor H. B. Griffiths for many stimulating conversations on this topic.     

Planes and processes

This article presented to Combinatorics 2006 is a survey of finite projective planes and the processes used to construct them. All non-translation planes are described, fundamental processes in translation planes are defined and some of these are used to connect semi-field flocks with symplectic spreads. Hermitian ovoids are connected to extensions of derivable nets, and three types of ‘lifting’ methods are discussed. Furthermore, hyperbolic fibrations and ‘regulus-inducing’ central collineation groups are connected to flocks of quadratic cones. Finally, hyper-reguli and multiple hyper-regulus replacement are considered.     

Mixtures of Global and Local Edgeworth Expansions and Their Applications

Edgeworth expansions which are local in one coordinate and global in the rest of the coordinates are obtained for sums of independent but not identically distributed random vectors. Expansions for conditional probabilities are deduced from these. Both lattice and continuous conditioning variables are considered. The results are then applied to derive Edgeworth expansions for bootstrap distributions, for Bayesian bootstrap distribution, and for the distributions of statistics based on samples from finite populations. This results in a unified theory of Edgeworth expansions for resampling procedures. The Bayesian bootstrap is shown to be second order correct for smooth positive “priors,” whenever the third cumulant of the “prior” is equal to the third power of its standard deviation. Similar results are established for weighted bootstrap when the weights are constructed from random variables with a lattice distribution.     

覆盖空间及粗糙集与拓扑的统一

引入覆盖空间,定义了其邻域、内部、闭包、测度等概念,研究了它们的性质.得出了粗糙集近似空间和拓扑空间都是具体覆盖空间的重要结论,从而用覆盖空间统一了粗糙集和拓扑.利用覆盖空间,得到了粗糙集和拓扑中更深刻的性质,从算子论和集合论的角度丰富和深化了粗糙集与拓扑的内容.     

Decompositions and Connectivity of Matching and Chessboard Complexes

New lower bounds for the connectivity degree of the r-hypergraph matching and chessboard complexes are established by showing that certain skeleta of such complexes are vertex decomposable, in the sense of Provan and Billera, and hence shellable. The bounds given by Björner et al. are improved for r \ge 3. Results on shellability of the chessboard complex due to Ziegler are reproven in the case r=2 and an affirmative answer to a question raised recently by Wachs for the matching complex follows. The new bounds are conjectured to be sharp.     

计算科学与工程本科及研究生教育的思考与实践

介绍一门新兴学科——计算科学与工程 (CSE) ,讨论该学科的本科与研究生教育的培养目标、课程设置、创新素质等 ,提出了计算科学与工程教育的几种培养模式 ,总结了本科、研究生教学实践的经验     

Aggregation functions and generalized convexity in fuzzy optimization and decision making

In this paper triangular norms and conorms are introduced and suitable definitions and properties are mentioned. Then, aggregation functions and their basic properties are defined. The averaging aggregation operators are defined and some interesting properties are derived. Moreover, we have extended concave and quasiconcave functions introducing t-quasiconcave and upper and lower starshaped functions. The main results concerning aggregation of generalized concave functions are presented and some extremal properties of compromise decisions by adopting aggregation operators are derived and discussed.     

Iterative solvers and stabilisation for mixed electrostatic and magnetostatic formulations

Mixed electrostatic and magnetostatic finite element formulations are considered. Solution methods for the resulting indefinite algebraic systems are investigated. Methods developed for the mixed formulations of the Stokes equations are modified in order to apply to the Maxwell equations: an efficient block preconditioner is proposed and a stabilised formulation is described. The different methods are applied to 2D and 3D examples.