Positivity and uniform exponential stability for Volterra integro-dynamical systems on time scales

The main objective of this study is two-fold: First, we provide necessary and sufficient conditions for the positivity of Volterra integro-dynamical systems on time scales by means of Metzler matrices. Secondly, we show that positivity of the system implies uniform exponential stability of the trivial solution under sufficient conditions.     

Further relationship between second-order cone and positive semidefinite matrix cone

It is well known that second-order cone (SOC) programming can be regarded as a special case of positive semidefinite programming using the arrow matrix. This paper further studies the relationship between SOCs and positive semidefinite matrix cones. In particular, we explore the relationship to expressions regarding distance, projection, tangent cone, normal cone and the KKT system. Understanding these relationships will help us see the connection and difference between the SOC and its PSD reformulation more clearly.     

Contingent cone to a set defined by equality and inequality constraints at a Fréchet differentiable point

In this paper, we prove equality expression for the contingent cone and the strict normal cone to a set determined by equality and/or inequality constraints at a Fréchet differentiable point. A similar result has appeared before in the literature under the assumption that all the constraint functions are of classC or under the assumption that the functions are strictly differentiable at the point in question. Our result has applications to the calculation of various kinds of tangent cones and normal cones.This research was supported, in part by the National Science and Engineering Research Council of Canada under Grant No. OGP-41983.The authors would like to thank D. E. Ward for his many helpful comments.     

Dimension of asymptotic cones of Lie groups

We compute the covering dimension of the asymptotic cone ofa connected Lie group. For simply connected solvable Lie groups,this is the codimension of the exponential radical. As an application of the proof, we give a characterization ofconnected Lie groups that quasi-isometrically embed into a nonpositivelycurved metric space. Received February 6, 2007.     

二阶锥线性互补问题的低阶罚函数算法

本文研究了二阶锥线性互补问题的低阶罚函数算法.利用低阶罚函数算法将二阶锥线性互补问题转化为低阶罚函数方程组,获得了低阶罚函数方程组的解序列在特定条件下以指数速度收敛于二阶锥线性互补问题解的结果,推广了二阶锥线性互补问题的幂罚函数算法.数值实验结果验证了算法的有效性.     

Surface-tension-driven flow in a slender cone

After a droplet has broken away from a slender thread or jetof liquid, the tip of the thread or jet recoils rapidly. Atthe moment of break-off, the tip of the thread/jet is observedto have the shape of a cone close to the bifurcation point.In this paper, we study the evolution of an ideal fluid whichis initially conical, where the only force acting on the fluidis due to surface tension. We find an asymptotic solution tothe problem in terms of the aspect ratio of the cone which isassumed to be small. Using a similarity transformation, whichis valid for small times after the bifurcation, we identifya rapidly oscillating non-linear wave which propagates awayfrom the tip, as observed in experiments.     

四阶奇异边值问题两个正解的存在性

本文利用锥压缩和锥拉伸不动点定理,给出了四阶微分方程奇异边值问题两 个C2[0,1]和C3[0,1]正解的存在性.     

Connectedness of Cone Superefficient Point Sets in Locally Convex Topological Vector Spaces

This paper studies the connectedness of the cone superefficient point set in locally convex topological vector spaces. First, we prove a scalarization theorem for a cone superefficient point set. From this result, we obtain the connectedness of a cone superefficient point set under the conditions that the set is cone convex and cone weakly compact.     

全连续算子的歧点

本文得到全连续算子和锥映象的新的歧点和渐近歧点定理,并指出它们的固有值的某种全局特征．     

A Class of Cone Bounded Quasiconvex Mappings in Topological Vector Spaces

Within the context of cone-ordered topological vector spaces, this paper introduces the concepts of cone bounded point and cone bounded set for vector set. With their aid, a class of new cone quasiconvex mappings in topological vector spaces is defined, and their fundamental properties are presented. The relationships between the cone bounded quasiconvex mapping defined in this paper and cone convex mapping, and other known cone quasiconvex mapping are also discussed.     

Construction of proximal distances over symmetric cones

Abstract

This paper is devoted to the study of proximal distances defined over symmetric cones, which include the non-negative orthant, the second-order cone and the cone of positive semi-definite symmetric matrices. Specifically, our first aim is to provide two ways to build them. For this, we consider two classes of real-valued functions satisfying some assumptions. Then, we show that its corresponding spectrally defined function defines a proximal distance. In addition, we present several examples and some properties of this distance. Taking into account these properties, we analyse the convergence of proximal-type algorithms for solving convex symmetric cone programming (SCP) problems, and we study the asymptotic behaviour of primal central paths associated with a proximal distance. Finally, for linear SCP problems, we provide a relationship between the proximal sequence and the primal central path.     

Characterization of subdual latticial cones in Hilbert spaces by the isotonicity of the metric projection

The subdual latticial cones in Hilbert spaces are characterized by the isotonicity of a generalization of the positive part mapping which can be expressed in terms of the metric projection only. Although Németh characterized the positive cone of Hilbert lattices with the metric projection and ordering only [A.B. Németh, Characterization of a Hilbert vector lattice by the metric projection onto its positive cone, J. Approx. Theory 123 (2) (2003), pp. 295–299.], this has been done for the first time for subdual latticial cones in this article. We also note that the normal generating pointed closed convex cones for which the projection onto the cone is isotone are subdual latticial cones, but there are subdual latticial cones for which the metric projection onto the cone is not isotone [G. Isac, A.B. Németh, Monotonicity of metric projections onto positive cones of ordered Euclidean spaces, Arch. Math. 46 (6) (1986), pp. 568–576; G. Isac, A.B. Néemeth, Every generating isotone projection cone is latticial and correct, J. Math. Anal. Appl. 147 (1) (1990), pp. 53–62; G. Isac, A.B. Németh, Isotone projection cones in Hilbert spaces and the complementarity problem, Boll. Un. Mat. Ital. B 7 (4) (1990), pp. 773–802; G. Isac, A.B. Németh, Projection methods, isotone projection cones, and the complementarity problem, J. Math. Anal. Appl. 153 (1) (1990), pp. 258–275; G. Isac, A.B. Németh, Isotone projection cones in Eucliden spaces, Ann. Sci. Math Québec 16 (1) (1992), pp. 35–52].     

Super-efficiency of vector optimization in Banach spaces

Using variational analysis, in terms of the Clarke normal cone, we consider super-efficiency of vector optimization in Banach spaces. We establish some characterizations for super-efficiency. In particular, dropping the assumption that the ordering cone has a bounded base, we extend a result in Borwein and Zhuang [J.M. Borwein, D. Zhuang, Super-efficiency in vector optimization, Trans. Amer. Math. Soc. 338 (1993) 105-122] to the nonconvex setting.     

Some recurrence formulas for box splines and cone splines

A degree elevation formula for multivariate simplex splines was given by Micchelli and extended to hold ]or multivariate Dirichlet splines in [8]. We report similar formulae for multivariate cone splines and box splsplines andines. To this end, we utilize a relation due to Dahmen and Micchelli that connects box cone splines and a degree reduction formulagiven by Cohen, Lyche, and Riesenfeld in [2].     

Generalization of the Dubovitzky-Milutyn optimality conditions

Various types of conical approximation of sets are discussed. The notions of an external cone and an internal cone result in a strengthened separation theorem. Based on this theorem, some generalizations of the Dubovitzky-Milutyn optimality conditions are given.This research was sponsored by the Institute of Automatic Control, Department of Electronics, Technical University, Warsaw, Poland.     

Stability in cellular neural networks with a piecewise constant argument

In this paper, by using the concept of differential equations with piecewise constant arguments of generalized type [1], [2], [3] and [4], a model of cellular neural networks (CNNs) [5] and [6] is developed. The Lyapunov-Razumikhin technique is applied to find sufficient conditions for the uniform asymptotic stability of equilibria. Global exponential stability is investigated by means of Lyapunov functions. An example with numerical simulations is worked out to illustrate the results.     

Some topological properties in optimization theory

We study some topological properties of the vector sum of two sets, and we introduce the concept of strong cone compactness, a slightly strengthened version of the notion of cone compactness, which is used frequently in vector optimization. Furthermore, we establish a generalization of the well-known fact that the continuous image of a compact set is compact.     

锥拟凸集值映射与集值映射的锥半连续性

本文借助锥界集定义了一种新的锥拟凸集值映射,并且利用广义Minkowski泛函讨论了锥半连续及锥外上半连续集值映射的锥拟凸性．     

一致椭圆型算子边值问题变号解的存在性

利用Banach空间锥理论、算子的指数理论、上下解理论研究了含有一致椭圆型算子的椭圆边值问题变号解的存在性,同时分别得到了一个正解和一个负解.特别当非线性项是奇函数时,该边值问题至少存在一个正解,一个负解和两个变号解.     

Category with a natural cone

Generally, in homotopy theory a cylinder object (or, its dual, a path object) is used to define homotopy between morphisms, and a cone object is used to build exact sequences of homotopy groups. Here, an axiomatic theory based on a cone functor is given. Suspension objects are associated to based objects and cofibrations, obtaining homotopy groups referred to an object and relative to a cofibration, respectively. Exact sequences of these groups are built. Algebraic and particular examples are given. We point out that the main results of this paper were already stated in [3], and the purpose of this article is to give full details of the foregoing.