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    25 June 2008, Volume 28 Issue 3 Previous Issue    Next Issue
    Articles

    On the {\boldmath ^psl(2|2)(2)k} Current
    Superalgebra and Conformal Field Theory

    Ding Xiangmao;Wang Guidong;Wang Shikun
    Acta mathematica scientia,Series A. 2008, 28 (3):  393-402. 
    Abstract ( 1898 )   RICH HTML PDF (371KB) ( 1229 )   Save

    The twisted Kac-Moody Lie superalgebra ^psl(2|2)(2)k
    is investigated by means of the vector coherent state method and
    obtained the differential operators realization.
    The authors get the free field representation of
    ^psl(2|2)(2)k, which is the subalgebra of
    ^gl(2|2)(2)k modulo the Z4-outer
    automorphism, the CFT has central charge 2.
    \noindent{\bf Key words:}Kac-Moody superalgebra; Differential operator realization; Free field realization; Conformal field theory.

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    Maximum Genus of Graphs Embedded in the Klein Bottle
    Huang Yuanqiu ;Tang Ling ;Liu Yanpei
    Acta mathematica scientia,Series A. 2008, 28 (3):  403-411. 
    Abstract ( 1936 )   RICH HTML PDF (371KB) ( 1241 )   Save
    Let ϕ:GS be a 2-cell embedding of a graph G into a surface S. If all faces of G are consecutively adjacent, equivalently the dual graph of the embedded graph G contains a Hamilton circuit, then the embedding ϕ is said to be a consecutively adjacent face embedding. In this paper the authors study the maximum genus of a graph that admits a consecutively adjacent face embedding in the Klein Bottle.
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    Quadratic Finite Volume Element Method Along Characteristics

    for the Semiconductor Device of Heat Conduction:

    H1Error Estimates

    Chen Chuanjun; Yuan Yirang
    Acta mathematica scientia,Series A. 2008, 28 (3):  412-423. 
    Abstract ( 2046 )   RICH HTML PDF (412KB) ( 1195 )   Save
    A fully discrete quadratic finite volume element method along characteristics for the semiconductor device of heat conduction is given, which is used by piecewise lagrange quadratic trial function and piecewise constant test function. Under general conditions, an optimal H1 error estimate is obtained.
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    Global Structure of Positive Solutions of Singular Nonlinear Sturm-Liouville Problems

    Sun Jingxian ;Li Hongyu
    Acta mathematica scientia,Series A. 2008, 28 (3):  424-433. 
    Abstract ( 2146 )   RICH HTML PDF (328KB) ( 1316 )   Save
    In this paper, the following nonlinear Sturm-Liouville problem
    {u
    is discussed by topological methods.
    In the case that the nonlinear term is non-singular or singular,
    global structure of the positive solution set of the above problem is obtained,
    and the existence of positive solutions
    of the above problem is proved under the condition that the nonlinear term f(x,u) does not satisfy f(x,u)≥0(u≥0).
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    A Phragmen-Lindelof Theorem for Plurisubharmonic Functions
    Wang Guang ; Wu Mijing
    Acta mathematica scientia,Series A. 2008, 28 (3):  434-437. 
    Abstract ( 1774 )   RICH HTML PDF (243KB) ( 1221 )   Save
    In this paper, a Phragmen-Lindelof theorem for plurisubharmonic functions is given, through which a result of [8] is extended.
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    The Henig Efficient Subdifferential of Set-valued Mapping

    and Stability

    Yu Guolin;Liu Sanyang
    Acta mathematica scientia,Series A. 2008, 28 (3):  438-446. 
    Abstract ( 2033 )   RICH HTML PDF (340KB) ( 1376 )   Save
    In normed linear spaces, the concepts of cone-Henig efficient subgradient
    and cone-Henig efficient subdifferential for a set-valued mapping are introduced. By using the convex set separation theorem, the existence theorem for cone-Henig efficient subdifferential is proposed, and the sufficient
    and necessary condition for a linear functional being a cone-Henig efficient subgradient is established. Finally, the stability problem for a kind of perturbed set-valued opimization problem is considered in sense of Henig efficiency.
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    Convergence for Pairwise NQD Random Variables
    chenpingyan
    Acta mathematica scientia,Series A. 2008, 28 (3):  447-453. 
    Abstract ( 1537 )   RICH HTML PDF (231KB) ( 1282 )   Save
    In this paper, the author discusses the L^r convergence for pairwise NQD
    random variables under r-th Ces\`aro uniform integrability, which is the same as that in the independent case.
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    Stability and Traveling Fronts in Lotka-Volterra Cooperation

    Model with Stage Structure

    Wu Shiliang ;Li Wantong
    Acta mathematica scientia,Series A. 2008, 28 (3):  454-464. 
    Abstract ( 2628 )   RICH HTML PDF (385KB) ( 1445 )   Save
    In this paper, the authors derive and study a delayed diffusion system, which models the interaction between the two species, the adult members of
    which are in cooperation. By using the method of sub- and super-solutions due to Redlinger, we show that the diffusive delay model generates simple global dynamics, i.e., the zero steady state and the boundary equilibria are linear unstable and the unique positive steady state is globally asymptotically stable. We also establish the existence of traveling wave fronts connecting the zero solution of this equation with the unique positive steady state.
    The approach used in this paper is the upper-lower solutions technique and the monotone iteration recently developed by Wang, Li and Ruan for reaction-diffusion systems with spatio-temporal delays.
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    A Compensatory Phenomenon to the Classical Sphere Theorem
    Wang Peihe;Shen Chunli
    Acta mathematica scientia,Series A. 2008, 28 (3):  465-471. 
    Abstract ( 1539 )   RICH HTML PDF (328KB) ( 1306 )   Save

    This paper discusses the topology of manifolds with a small well of positive k-th Ricci curvature and generalizes the classical sphere theorem. Also, the authors will describe an interesting compensatory phenomenon of the manifold with respect to the classical sphere theorem.

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    The Properties of cut* Topological Spaces
    Peng Liangxue;Huang Guifang
    Acta mathematica scientia,Series A. 2008, 28 (3):  472-479. 
    Abstract ( 1950 )   RICH HTML PDF (322KB) ( 1155 )   Save
    In this note, the class of cut*spaces are introduced.
    A connected topological space X is called a cut* space, if X\setminus \{x\} is connected for any x\in X, and X\setminus \{x,y\} is not connected for any distinct points x,y\in X. The properties of cut* spaces are discussed. The authors show that if X is a cut* spaces, then \{x\} is open or closed for any x\in X, and X has infinite closed points. The authors also discuss the properties of some special cut* spaces, which satisfy that X\setminus \{x\} is COTS for any x\in X. The authors show that there doesn't exisxt a cut* space X, satisfying that X\setminus \{x\} is a irreducible cut space for any x\in X. In the last part of the note, the authors show that X is compact or Lindel\"of, if X is a cut* space and X\setminus \{x\} is LOTS for any x\in X.
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    Full Regularity of {\boldmath p}-Harmonic Type Systems Below

    the Critical Growth

    Zheng Shenzhou;Zhao Shule
    Acta mathematica scientia,Series A. 2008, 28 (3):  480-488. 
    Abstract ( 1710 )   RICH HTML PDF (320KB) ( 1237 )   Save
    For p\geq 2, the authors establish that each weak solution of a class of degenerate elliptic systems below the critical growth belongs to Morrey spaces. Furthermore, the authors obtain that the first derivative of each weak solution is locally H\"older continuous under additional conditions.
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    New Perturbation Results on Frames in Hilbert Spaces
    Li Dengfeng ;Yang Lijun
    Acta mathematica scientia,Series A. 2008, 28 (3):  489-499. 
    Abstract ( 1926 )   RICH HTML PDF (321KB) ( 1356 )   Save

    In this paper, some new results of frame perturbation in Hilbert spaces are obtained.The authors also discuss perturbations of Riesz bases, near-Riesz bases and Riesz frames.Moreover, it is showed that many known results are corollaries of the results.

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    A Spectral Characterization for Stability of C0-semigroups

    on ∑e1 Type Banach Spaces

    Su Weigang; Zhong Huaijie
    Acta mathematica scientia,Series A. 2008, 28 (3):  500-507. 
    Abstract ( 1907 )   RICH HTML PDF (347KB) ( 1231 )   Save
    This paper discusses the special properties of the spectrum of bounded
    linear operators in a class of indecomposable e1 type Banach spaces;gives a spectral characterization for stability of uniformly bounded C0-semigroups on e1 type Banach spaces, and gives an application to the stability theorem.
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    On the Completeness and Closure of Random Systems { tλn (ω) } in a Weighted Banach Space

    Yang Xiangdong; Deng Guantie
    Acta mathematica scientia,Series A. 2008, 28 (3):  508-514. 
    Abstract ( 2003 )   RICH HTML PDF (255KB) ( 1244 )   Save
    In this paper, the authors investigate the completeness and closure of random systems{ tλn (ω) } in the weighted Banach space C_{\alpha}, where C_{\alpha} denotes the Banach spaces consisting of functions of one complex variable continuous on the right half real axis and satisfying |f(t)|{\rm e}^{-\alpha(t)}\rightarrow0~(t\rightarrow +\infty).
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    Three Nontrival Positive Solutions for Second Order Three Point

    Boundary Value Problems with Sign Changing Nonlinearities
    Li Cheng;Liu Lishan
    Acta mathematica scientia,Series A. 2008, 28 (3):  515-522. 
    Abstract ( 2247 )   RICH HTML PDF (279KB) ( 1306 )   Save
    In this paper, the existence of multiple nontrival positive solutions for a class of singular second order three point boundary value problems with sign changing nonlinearities is investigated. Growth conditions are imposed on f, which yield the existence of at least three nontrival positive solutions by using the Leggett-Williams fixed point theorem.
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    Universal Admissibility of Linear Estimators in Growth Curve

    Model with Respect to Restricted Parameter Sets

    Zhang Shangli;Qin Hong
    Acta mathematica scientia,Series A. 2008, 28 (3):  523-529. 
    Abstract ( 1776 )   RICH HTML PDF (316KB) ( 1309 )   Save
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    Some Integral Criteria for α -Normal Functions
    Liu Yongmin;Hu Zhangjian
    Acta mathematica scientia,Series A. 2008, 28 (3):  530-534. 
    Abstract ( 1922 )   RICH HTML PDF (245KB) ( 1148 )   Save
    For 0< \alpha< \infty, N^\alpha is the class of meromorphic
    functions f defined in the unit disk D satisfying \sup\limits_{z\in D}(1-|z|^2)^\alpha f^\#(z)<\infty, where f^\#(z)=|f'(z)|/(1+|f(z)|^2). Some new characterizations of the \alpha -normal functions are given for 0< \alpha< 1. Characterizations are given in terms of the Bergman-Carleson measure conditions and the compact Bergman-Carleson conditions.
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    Strong Converse Inequalities for Weighted Simultaneous

    Approximation by Gamma Operators in Lp (1≤p ≤∞) Spaces

    Qi Qiulan; Guo Shunsheng;Huang Suxia
    Acta mathematica scientia,Series A. 2008, 28 (3):  537-545. 
    Abstract ( 2105 )   RICH HTML PDF (296KB) ( 1304 )   Save
    In this paper, the authors consider the weighted simultaneous approximation by the Gamma operator and establish the strong converse inequality of type B for the operator with the weighted K-functional K^2_{\varphi}(f, t^2)_{w,p} in the space L_p\;(1\le p\le \infty).
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    On a Class of Singularly Perturbed Problems with

    Boundary Perturbation

    Tang Rongrong
    Acta mathematica scientia,Series A. 2008, 28 (3):  546-552. 
    Abstract ( 1788 )   RICH HTML PDF (271KB) ( 1244 )   Save
    By using the asymptotic theory, a class of singularly perturbed problems with boundary perturbation is considered. Under the appropriate conditions, the asymptotic solution and the existence conditions of the solution are obtained, and from the result a propagation problem in mural wave is applied.
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    MLE of Generalized Linear Model Randomly Censored with
    Incomplete Information
    Xiao Zhihong;Liu Luqin
    Acta mathematica scientia,Series A. 2008, 28 (3):  553-564. 
    Abstract ( 1949 )   RICH HTML PDF (368KB) ( 1254 )   Save
    In this paper, one defines the generalized linear models(GLM) based on the observed data with incomplete information and random censorship under the case that regressors are given and regressors are stochastic, respectively. Under the given conditions, one discusses the existence and uniqueness of the solution on the likelihood equations with respect to the parameter vector of the two models, obtains and proves the consistency and asymptotical
    normality of the maximum likelihood estimators(MLE) on the two models, respectively.
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    The Holder Continuity of Quasiconformal Mappings in Bounded Convex Domains

    Zheng Ningguo; Chu Yuming
    Acta mathematica scientia,Series A. 2008, 28 (3):  565-569. 
    Abstract ( 2190 )   RICH HTML PDF (279KB) ( 1308 )   Save
    By using the modulus of family of curves, the global Holder continuity of the K-quasiconformal mapping f which maps bounded convex domain D onto Bn is obtained, and the Holder exponent α=K1/(1-n) is optimal.
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    Generalized Augmented Lagrangian Duality Theory and

    Applications in Vector Optimization Problems

    Chen Zhe
    Acta mathematica scientia,Series A. 2008, 28 (3):  570-577. 
    Abstract ( 1948 )   RICH HTML PDF (291KB) ( 1224 )   Save
    In this paper, the author introduces a generalized augmented Lagrangian for minimizing an extended vector-valued function. Based on the generalized augmented Lagrangian, the author constructs set-valued dual functions and dual optimization problems, obtain weak and strong duality results without any convexity required, apply the results for solving a constrained vector optimization problem. The results improve and generalize some known results.
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    Stability and Hopf Bifurcation of an SIS Model with Species

    Logistic Growth and Saturating Infect Rate

    Xu Weijian;
    Acta mathematica scientia,Series A. 2008, 28 (3):  578-584. 
    Abstract ( 1956 )   RICH HTML PDF (357KB) ( 1161 )   Save

    In this paper, an SIS infective model with species Logistic growth
    and saturating infective rate is studied. The author discusses the existence and the globally asymptotical stability of the equilibrium, and obtains the threshold value at which disease is eliminated, which is just the basic rebirth number R_{0}=1. The author proves that whenR_{0}<1, the non-disease equilibrium is globally asymptotically stable; when R_{0}>1 and \alpha K\leq 1, the positive equilibrium is globally asymptotically
    stable; when R_{0}>1 and \Delta =0 , a Hopf bifurcation occurs near the positive equilibrium; when R_{0}>1 and \Delta <0 , the system has a unique limit cycle which is stable near the outside of the positive equilibrium.

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