三对角逆M-矩阵

In this paper we study a class of inverse M-matrices:tridiagonal inverse M-matrices,Graph theory is used to discuss the structure and properties of tridiagonal inverse M-matrices,A sufficient and necessary condtion for a nonnegative tridiagonal matrix to be an inverse M-matrix is given.Finally,it is proved that the set of the inverses of M-matrices with unipathic is closed under Hadamard product.     

Bloch Constant of Holomorphic Mappings on the Unit Ball of ℂ<Superscript><Emphasis Type="Italic">n</Emphasis></Superscript>*

In this paper, the authors establish distortion theorems for various subfamilies Hk(B) of holomorphic mappings defined in the unit ball in Cn with critical points, where k is any positive integer. In particular, the distortion theorem for locally biholomorphic mappings is obtained when k tends to oo. These distortion theorems give lower bound son det f(z) and Redet f'(z). As an application of these distortion theorems, the authors give lower and upper bounds of Bloch constants for the subfamilies βk (M) of holomorphic mappings. Moreover, these distortion theorems are sharp. When B is the unit disk in C, these theorems reduce to the results of Liu and Minda. A new distortion result of Re det f'(z) for locally biholomorphic mappings is also obtained.     

A Characterization of Complete Bounded Domain

1 IntroductionThis paper is concerned with biholomorphic mappings between two bounded domains D andG both in C". Consequently, an important question is whether the domain D is biholomorphicto G? We give an answer for this question under a very weak condition.Let D be a bounded domain and Bn the unit ball in Cn. Let T(D) be the holomorphictangent bundle of D. We will identify T(D) with D × Cn. Let H(D1, D2) be the family ofholomorphic mappings from D1 to D2. We introduce the followin…     

本刊英文版2014年57卷第3期摘要

<正>From microscopic theory to macroscopic theory—symmetries and order parameters of rigid molecules XU JieZHANG PingWen Abstract Density functional theory is used to describe the phase behaviors of rigid molecules.The construction of the kernel function is discussed.Excluded-volume potential is calculated for two types of molecules with C2v symmetry.Molecular symmetries lead to the symmetries of the kernel function and the density function,enabling     

Banach空间半直线上非线性二阶微分方程组正解的存在性

In this paper, the cone theory and MSnch fixed point theorem combined with the monotone iterative technique are used to investigate the positive solutions for a class of systems of nonlinear singular differential equations with multi-point boundary value conditions on the half line in a Banach space. The conditions for the existence of positive solutions are formulated. In addition, an explicit iterative approximation of the solution is also derived.     

Bloch Constant of Holomorphic Mappings on the Unit Ball of C~n

In this paper,the authors establish distortion theorems for various subfamilies H_k(B)of holomorphic mappings defined in the unit ball in C~n with critical points,where k is any positive integer.In particular,the distortion theorem for locally biholomorphic mappings is obtained when k tends to ∞.These distortion theorems give lower bounds on|det f′(z)|and Re det f′(z).As an application of these distortion theorems,the authors give lower and upper bounds of Bloch constants for the subfamiliesβ_k(M)of holomorphic mappings.Moreover,these distortion theorems are sharp.When B is the unit disk in C,these theorems reduce to the results of Liu and Minda.A new distortion result of Re det f′(z)for locally biholomorphie mappings is also obtained.     

Orbital-Free Density Functional Theory for Molecular Structure Calculations

We give here an overview of the orbital-free density functional theory that is used for modeling atoms and molecules.We review typical approximations to the kinetic energy,exchange-correlation corrections to the kinetic and Hartree energies, and constructions of the pseudopotentials.We discuss numerical discretizations for the orbital-free methods and include several numerical results for illustrations.     

LINEAR TRANSPORT EQUATION WITH INDEFINITE COLLISION OPERATOR

The operator theory on indefinite inner product spaces is used to discuss the halfrange problem of linear transport equation with indefinite collision operator. A counterexample to [1] is given and a relation between measures of nonuniqueness and noncompleteness is established.     

Approximate Controllability of Neutral Functional Differential Systems with State-Dependent Delay

This paper deals with the approximate controllability of semilinear neutral functional differential systems with state-dependent delay. The fractional power theory and α-norm are used to discuss the problem so that the obtained results can apply to the systems involving derivatives of spatial variables. By methods of functional analysis and semigroup theory, sufficient conditions of approximate controllability are formulated and proved. Finally, an example is provided to illustrate the applications of the obtained results.     

Iterative Algorithm with Mixed Errors for Solving a New System of Generalized Nonlinear Variational-Like Inclusions and Fixed Point Problems in Banach Spaces

A new system of generalized nonlinear variational-like inclusions involving Amaximal m-relaxed η-accretive(so-called,(A, η)-accretive in [36]) mappings in q-uniformly smooth Banach spaces is introduced, and then, by using the resolvent operator technique associated with A-maximal m-relaxed η-accretive mappings due to Lan et al., the existence and uniqueness of a solution to the aforementioned system is established. Applying two nearly uniformly Lipschitzian mappings S1 and S2 and using the resolvent operator technique associated with A-maximal m-relaxed η-accretive mappings, we shall construct a new perturbed N-step iterative algorithm with mixed errors for finding an element of the set of the fixed points of the nearly uniformly Lipschitzian mapping Q =(S1, S2) which is the unique solution of the aforesaid system. We also prove the convergence and stability of the iterative sequence generated by the suggested perturbed iterative algorithm under some suitable conditions. The results presented in this paper extend and improve some known results in the literature.     

A Geometric Characterization of Poly-antimatroids

The concept of "antimatroid with repetition" was coined by Bjorner, Lovasz and Shor in 1991 as an extension of the notion of antimatroid in the framework of non-simple languages [Björner A., L. Lovász, and P. R. Shor, Chip-firing games on graphs, European Journal of Combinatorics 12 (1991), 283–291]. There are some equivalent ways to define antimatroids. They may be separated into two categories: antimatroids defined as set systems and antimatroids defined as languages. For poly-antimatroids we use the set system approach. In this research we concentrate on interrelations between geometric, algorithmic, and lattice properties of poly-antimatroids. Much to our surprise it turned out that even the two-dimensional case is not trivial.     

Antimatroids and Balanced Pairs

We generalize the $\frac{1}{3}$ – $\frac{2}{3}$ conjecture from partially ordered sets to antimatroids: we conjecture that any antimatroid has a pair of elements x,y such that x has probability between $\frac{1}{3}$ and $\frac{2}{3}$ of appearing earlier than y in a uniformly random basic word of the antimatroid. We prove the conjecture for antimatroids of convex dimension two (the antimatroid-theoretic analogue of partial orders of width two), for antimatroids of height two, for antimatroids with an independent element, and for the perfect elimination antimatroids and node search antimatroids of several classes of graphs. A computer search shows that the conjecture is true for all antimatroids with at most six elements.     

A single-element extension of antimatroids

An antimatroid is a family of sets which is accessible, closed under union, and includes an empty set. A number of examples of antimatroids arise from various kinds of shellings and searches on combinatorial objects, such as, edge/node shelling of trees, poset shelling, node-search on graphs, etc. (Discrete Math. 78 (1989) 223; Geom. Dedicata 19 (1985) 247; Greedoids, Springer, Berlin, 1980) [1, 2 and 3]. We introduce a one-element extension of antimatroids, called a lifting, and the converse operation, called a reduction. It is shown that a family of sets is an antimatroid if and only if it is constructed by applying lifting repeatedly to a trivial lattice. Furthermore, we introduce two specific types of liftings, 1-lifting and 2-lifting, and show that a family of sets is an antimatroid of poset shelling if and only if it is constructed from a trivial lattice by repeating 1-lifting. Similarly, an antimatroid of edge-shelling of a tree is shown to be constructed by repeating 2-lifting, and vice versa.     

Linear values for interior operator games

Interior operator games were introduced by Bilbao et al. (2005) as additive games restricted by antimatroids. In that paper several interesting cooperative games were shown as examples of interior operator games. The antimatroid is a known combinatorial structure which represents, in the game theory context, a dependence system among the players. The aim of this paper is to study a family of values which are linear functions and satisfy reasonable conditions for interior operator games. Two classes of these values are considered assuming particular properties.     

Excluded–Minor Characterizations of Antimatroids arisen from Posets and Graph Searches

An antimatroid is a family of sets such that it contains an empty set, and it is accessible and closed under union of sets. An antimatroid is a ’dual’ or ‘antipodal’ concept of matroid.We shall show that an antimatroid is derived from shelling of a poset if and only if it does not contain a minor isomorphic to S₇ where S₇ is the smallest semimodular lattice that is not modular (See Fig. 1). It is also shown that an antimatroid is a node-search antimatroid of a digraph if and only if it does not contain a minor isomorphic to D₅ where D₅ is a lattice consisting of five elements Ø {x},{y}, {x, y} and {x, y, z}. Furthermore, an antimatroid is shown to be a node-search antimatroid of an undirected graph if and only if it does not contain D₅ nor S₁₀ as a minor: S₁₀ is a locally free lattice consisting of ten elements shown in Fig. 2.     

Poset extensions, convex sets, and semilattice presentations

The paper is devoted to an algebraic and geometric study of the feasible set of a poset, the set of finite probability distributions on the elements of the poset whose weights satisfy the order relationships specified by the poset. For a general poset, this feasible set is a barycentric algebra. The feasible sets of the order structures on a given finite set are precisely the convex unions of the primary simplices, the facets of the first barycentric subdivision of the simplex spanned by the elements of the set. As another fragment of a potential complete duality theory for barycentric algebras, a duality is established between order-preserving mappings and embeddings of feasible sets. In particular, the primary simplices constituting the feasible set of a given finite poset are the feasible sets of the linear extensions of the poset. A finite poset is connected if and only if its barycentre is an extreme point of its feasible set. The feasible set of a (general) disconnected poset is the join of the feasible sets of its components. The extreme points of the feasible set of a finite poset are specified in terms of the disjointly irreducible elements of the semilattice presented by the poset. Semilattices presented by posets are characterised in terms of various distributivity concepts.     

Convexity properties for interior operator games

Interior operator games arose by abstracting some properties of several types of cooperative games (for instance: peer group games, big boss games, clan games and information market games). This reason allow us to focus on different problems in the same way. We introduced these games in Bilbao et al. (Ann. Oper. Res. 137:141–160, 2005) by a set system with structure of antimatroid, that determines the feasible coalitions, and a non-negative vector, that represents a payoff distribution over the players. These games, in general, are not convex games. The main goal of this paper is to study under which conditions an interior operator game verifies other convexity properties: 1-convexity, k-convexity (k≥2 ) or semiconvexity. But, we will study these properties over structures more general than antimatroids: the interior operator structures. In every case, several characterizations in terms of the gap function and the initial vector are obtained. We also find the family of interior operator structures (particularly antimatroids) where every interior operator game satisfies one of these properties.     

Combinatorial representation and convex dimension of convex geometries

We develop a representation theory for convex geometries and meet distributive lattices in the spirit of Birkhoff's theorem characterizing distributive lattices. The results imply that every convex geometry on a set X has a canonical representation as a poset labelled by elements of X. These results are related to recent work of Korte and Lovász on antimatroids. We also compute the convex dimension of a convex geometry.Supported in part by NSF grant no. DMS-8501948.