A stable theorem of the alternative: an extension of the gordan theorem

A theorem with a number of equivalent alternatives is proposed as an extension of the classical Gordan theorem of the alternative. The theorem can handle nonzero unrestricted variables which cannot be directly treated by ordinary theorems of the alternative. Like the Gordan theorem, the extended theorem has the stability feature that small perturbations in the data will not invalidate an alternative that is in force. The theorem has useful applications in establishing the boundedness and uniqueness of feasible points of polyhedral sets and of solutions to linear programming problems.     

Minkowski-type and Alexandrov-Type Theorems for Polyhedral Herissons

Classical H. Minkowski theorems on existence and uniqueness of convex polyhedra with prescribed directions and areas of faces as well as the well-known generalization of H. Minkowski uniqueness theorem due to A.D. Alexandrov are extended to a class of nonconvex polyhedra which are called polyhedral herissons and may be described as polyhedra with injective spherical image.     

Polyhedral extensions of some theorems of linear programming

Three theorems of linear programming form our starting point: Tucker's theorem (1956) concerning the existence of optimal solutions satisfying the complementary slackness conditions strictly, and Williams' two theorems (1970) concerning the coordinatewise complementary behavior of feasible and optimal solutions. Here, we establish that the same phenomena hold in another, more versatile framework involving general polyhedral convexity. As one main application, the results are transferred into the context of the monotone complementarity problem. Several other theoretical applications are indicated.Research supported in part by the National Science Foundation under grant number MCS 79-05793 at the University of Illinois at Urbana-Champaign.     

Characteristics and structures of weak efficient surfaces of production possibility sets

This paper studies the characteristics and structure of the weak surface of the production possibility set. We apply techniques and methods of transferring a polyhedral cone from its intersection form to its sum form, identify an intersection representation of the production possibility set. We give the structure theorem of weak surface of the production possibility set, which includes three complementary slackness conditions. We define the input weak efficiency and output weak efficiency for different DEA models according to the representation of the intersection form. It investigates the characteristics of the weak surfaces, and proves the structure theorems of input weak DEA efficiency and output weak DEA efficiency. The structure theorems establish weighted combination of inputs and outputs that are weak DEA efficient. Numerical examples are provided for illustration.     

A multidirectional Dirichlet problem

B.E.J. Dahlberg’s theorems on the mutual absolute continuity of harmonic and surface measures, and on the unique solvability of the Dirichlet problem for Laplace’s equation with data taken in L^p spaces p > 2 ? δ are extended to compact polyhedral domains of ?ⁿ. Consequently, for q < 2 + δ, Dahlberg’s reverse Hölder inequality for the density of harmonic measure is established for compact polyhedra that additionally satisfy the Harnack chain condition. It is proved that a compact polyhedral domain satisfies the Harnack chain condition if its boundary is a topological manifold. The double suspension of the Mazur manifold is invoked to indicate that perhaps such a polyhedron need not itself be a manifold with boundary; see the footnote in Section 9. A theorem on approximating compact polyhedra by Lipschitz domains in a certain weak sense is proved, along with other geometric lemmas.     

Group-theoretic compactification of Bruhat-Tits buildings

Let GF denote the rational points of a semisimple group G over a non-archimedean local field F, with Bruhat-Tits building X. This paper contains five main results. We prove a convergence theorem for sequences of parahoric subgroups of GF in the Chabauty topology, which enables us to compactify the vertices of X. We obtain a structure theorem showing that the Bruhat-Tits buildings of the Levi factors all lie in the boundary of the compactification. Then we obtain an identification theorem with the polyhedral compactification (previously defined in analogy with the case of symmetric spaces). We finally prove two parametrization theorems extending the Bruhat-Tits dictionary between maximal compact subgroups and vertices of X: one is about Zariski connected amenable subgroups and the other is about subgroups with distal adjoint action.     

Minimum Distance to the Complement of a Convex Set: Duality Result

The subject of this paper is to study the problem of the minimum distance to the complement of a convex set. Nirenberg has stated a duality theorem treating the minimum norm problem for a convex set. We state a duality result which presents some analogy with the Nirenberg theorem, and we apply this result to polyhedral convex sets. First, we assume that the polyhedral set is expressed as the intersection of some finite collection of m given half-spaces. We show that a global solution is determined by solving m convex programs. If the polyhedral set is expressed as the convex hull of a given finite set of extreme points, we show that a global minimum for a polyhedral norm is obtained by solving a finite number of linear programs.     

Homogeneous programming and symmetrization

A polyhedral or piecewise linear homogeneous programming problem is shown through symmetrization to be equivalent to a linear one, yielding a duality theorem for polyhedral homogeneous programming. As a consequence of this duality, it follows that the simplex method can be used to solve such problems.     

Equivalent forms of a generalized KKM theorem and their applications

In this paper, we study various types of variational relation problems. We establish the existence of solutions for these types of problems and point out some important particular cases and their applications. We also show that some existence theorems of solution for these types of problems and some existence theorems of variational inclusion problems are equivalent to a generalized KKM theorem. Applying our results we obtain existence theorems of common fixed point, generalized maximal element theorems, a generalized coincidence theorems and a section theorem.     

On transitive topological group actions

We prove a general theorem on transitive topological group actions that give rise to almost ?ech-complete homogeneous spaces. This theorem implies the known open mapping theorems whose proof is a Baire category argument. As an application, we prove the uniform generalized Schönflies theorem generalizing Wright (1969) [19, Theorem 3].     

When do the Recession Cones of a Polyhedral Complex Form a Fan?

We study the problem of when the collection of the recession cones of a polyhedral complex also forms a complex. We exhibit an example showing that this is no always the case. We also show that if the support of the given polyhedral complex satisfies a Minkowski–Weyl-type condition, then the answer is positive. As a consequence, we obtain a classification theorem for proper toric schemes over a discrete valuation ring in terms of complete strongly convex rational polyhedral complexes.     

三角恒等式与初等几何定理的机械化证明

一、三角恒等式的机械化证明我们知道,适当选取模型,双曲几何、椭圆几何中的定理证明几乎可以全部化为三角函数与双曲函数的运算。即使在欧氏平面几何中,三角函数的应用有时也会使证明大大简化。但三角函数的运算往往是既繁琐又要很高的技巧,特别是当涉及的几何问题复杂时手算几乎是不可能的。吴文俊在文献[4,6]中指出,可以利用三角函数满足的代数关系及 Ritt-吴文俊原理机械化地证明三角函数公式。本文将给出更直接的方法,并用之于几何定理的证明。当定理涉及角度及方向时,该方法特别有效。     

A theorem of the closed graph type

The author proves a theorem about systems of sets which generalizes the closed graph theorem. To illustrate its application proofs, are given of several generalizations of the closed graph theorem, of selection theorems, a transitivity theorem for C^...-algebras and factorization theorems in Banach algebras.     

From an abstract maximal element principle to optimization problems,stationary point theorems and common fixed point theorems

In this paper, we first establish an existence theorem related with intersection theorem, maximal element theorem and common fixed point theorem for multivalued maps by applying an abstract maximal element principle proved by Lin and Du. Some new stationary point theorems, minimization problems, new fixed point theorems and a system of nonconvex equilibrium theorem are also given.     

An extension theorem for modular measures on effect algebras

We prove an extension theorem for modular measures on lattice ordered effect algebras. This is used to obtain a representation of these measures by the classical ones. With the aid of this theorem we transfer control theorems, Vitali-Hahn-Saks, Nikodym theorems and range theorems to this setting.     

GENERAL OPEN MAPPING THEOREMS FOR LINEAR TOPOLOGICAL SPACES

0IntroductionIntile1930's,thefirstoped1flappingtheoremforFr6clletspaceswasprovedbyS.B....htll].Sincethedtilevariousextellsiollsoftheopenmappingtheoremhaveapl)earedillsuccessiollforitsapplications(fordetails,see[4]).In1958,V.PtAkfoundoutthatoped1llappillgtheoremsareconllectedwithsolllecompleteness,alldheobtainedastrikillgextensiollofBallach'sclassicaltlleoreul,whichpoilltsoutthatcontinuouslillearmapsfi.olllB-colllpletespacesolltobarrelledspacesareoped['].1111965,T.Husaingaveaninlportalltope…     

Joint value-distribution theorems on Lerch zeta-functions. II

We give corrected statements of some theorems from [5] and [6] on joint value-distribution of Lerch zeta-functions (limit theorems, universality, functional independence). We also present a new direct proof of a joint limit theorem in the space of analytic functions and an extension of a joint universality theorem. Published in Lietuvos Matematikos Rinkinys, Vol. 46, No. 3, pp. 332–350, July–September, 2006.     

FC-空间上的鞍点定理及应用

在不具有任何凸性结构和线性结构的有限连续空间(简称FC-空间)中给出了一个鞍点定理.并应用此定理,在很弱的条件下证明了一些非空交定理及截口定理,推广了近期文献中的一些相关的结果.     

局部凸H-空间中的Ky Fan型截口定理及其应用

本文首先在局部凸Ｈ－空间中建立一个Ｆａｎ型截口定理,作为应用,我们Ｈ－在空间中获得了相交定理、重合定理和极大极小定理本文中定理把文献中的相应结果改进和推广到Ｈ－空间。     

Classical and approximate sampling theorems; studies in the and the uniform norm

The approximate sampling theorem with its associated aliasing error is due to J.L. Brown (1957). This theorem includes the classical Whittaker–Kotel’nikov–Shannon theorem as a special case. The converse is established in the present paper, that is, the classical sampling theorem for , 1p<∞, w>0, implies the approximate sampling theorem. Consequently, both sampling theorems are fully equivalent in the uniform norm.Turning now to -space, it is shown that the classical sampling theorem for , 1<p<∞ (here p=1 must be excluded), implies the -approximate sampling theorem with convergence in the -norm, provided that f is locally Riemann integrable and belongs to a certain class Λ^p. Basic in the proof is an intricate result on the representation of the integral as the limit of an infinite Riemann sum of |f|^p for a general family of partitions of ; it is related to results of O. Shisha et al. (1973–1978) on simply integrable functions and functions of bounded coarse variation on . These theorems give the missing link between two groups of major equivalent theorems; this will lead to the solution of a conjecture raised a dozen years ago.