Operating Points in Infinite Nonlinear Networks Approximated by Finite Networks

Given a nonlinear infinite resistive network, an operating point can be determined by approximating the network by finite networks obtained by shorting together various infinite sets of nodes, and then taking a limit of the nodal potential functions of the finite networks. Initially, by taking a completion of the node set of the infinite network under a metric given by the resistances, limit points are obtained that represent generalized ends, which we call ``terminals,' of the infinite network. These terminals can be shorted together to obtain a generalized kind of node, a special case of a 1-node. An operating point will involve Kirchhoff's current law holding at 1-nodes, and so the flow of current into these terminals is studied. We give existence and bounds for an operating point that also has a nodal potential function, which is continuous at the 1-nodes. The existence is derived from the said approximations.

     

A New Jacobi Elliptic Function Expansion Method for Solvinga Nonlinear PDE Describing Pulse Narrowing Nonlinear Transmission Lines

In this article, we apply the first elliptic function equation to find a new kind of solutions of nonlinear partial differential equations (PDEs) based on the homogeneous balance method, the Jacobi elliptic expansion method and the auxiliary equation method. New exact solutions to the Jacobi elliptic functions of a nonlinear PDE describing pulse narrowing nonlinear transmission lines are given with the aid of computer program, e.g. Maple or Mathematica. Based on Kirchhoff's current law and Kirchhoff's voltage law, the given nonlinear PDE has been derived and can be reduced to a nonlinear ordinary differential equation (ODE) using a simple transformation. The given method in this article is straightforward and concise, and can be applied to other nonlinear PDEs in mathematical physics. Further results may be obtained.     

Comparing First Order Theories of Modules over Group Rings

We consider R‐torsionfree modules over group rings RG, where R is a Dedekind domain and G is a finite group. We compare the (first order) theory T of al these modules and the theory T₀ of the finitely generated ones (so of RG‐lattices). It is easy to realize that they are equal iff R is a field. The obstruction is the existence of R‐divisible R‐torsionfree RG‐modules. Accordingly we consider R‐reduced R‐torsionfree RG‐modules for a local R. We show that the key conditions ensuring that their theory equals T₀ are: (1) RG‐lattices have a finite representation type; (2) each attice over the completion R̂G is isomorphic to the completion of some RG‐lattice.Some related questions are discussed.     

Random Matching of Several Infinite Populations

Random matching models with infinite populations present formal difficulties due to the lack of a law of large numbers for a continuum of random variables. In a previous paper (Alós-Ferrer, 1999), random matching processes for a continuum of agents were studied, proving their existence. The present work extends the analysis to the case of several populations, which includes general equilibrium buyers–sellers models, and evolutionary models with underlying asymmetric games.     

无限箭图的同调群

对任意箭图Q,我们研究路代数A=kQ的Hochschild同调群H_n(A)和同调群Tor_n^Ae(A,A),其中A^e是代数A的包络代数。在本文中,我们具体地给出了各次同调群和Hochschild同调群。     

Infinite Nests of Reguli

In this article, infinite versions of t-nests for t=q,(q-1), (q+1),2(q-1) and mixed nests of reguli are constructed. Furthermore, a classification of all group replaceable spreads is given.     

Φ混合AR(1)过程a.s.收敛性

本文对混合变量生成的一阶自回归过程建立了Ｍａｒｃｉｎｋｉｅｗｉｃｚ强大数定律．我们还给出了Ｈａｒｔｍａｎ－Ｗｉｎｔｎｅｒ重对数律在ＡＲ（１）上的结果．     

Comparing First Order Theories of Modules over Group Rings II: Decidability

We consider R‐torsionfree modules over group rings RG, where R is a Dedekind domain and G is a finite group. In the first part of the paper [4] we compared the theory T(RG) of all R‐torsionfree RG‐modules and the theory T₀(RG) of RG‐lattices (i. e. finitely generated R‐torsionfree RG‐modules), and we realized that they are almost always different. Now we compare their behaviour with respect to decidability, when RG‐lattices are of finite, or wild representation type.     

Justification of the Kirchhoff hypotheses and error estimation for two-dimensional models of anisotropic and inhomogeneous plates, including laminated plates

Asymptotic analysis of the problem describing deformation ofa thin cylindrical plate with clamped lateral side is performed.The problem is considered under the most general statement withthe plate being laminated and consisting of an arbitrary numberof nonhomogeneous and anisotropic (21 elastic moduli) layers.Explicit integral representations of the differential operatorswhich form the two-dimensional model of the plate are derived.In the case when the elastic moduli of each of the layers areconstant, these integral representations turn into algebraicones. The asymptotic procedure is justified with the help ofa weighted inequality of Korn's type. The error estimates obtainedgive a rigorous mathematical proof of both of Kirchhoff's hypotheses(kinematic and static) and shed light on the well-known intrinsicinconsistency of two of the hypotheses.     

无穷维L1空间至连续函数空间的等距逼近问题

证明了无穷维Ｌ~１空间至连续函数空间的等距逼近问题的回答是否定的．     

A Nonparametric Sequential Test with Power 1 for the Mean of Lévy-stable Laws with Infinite Variance

A nonparametric sequential test with power one for the mean of Lévy-stable laws with infinite variance is given. Our considerations are based on a law of the iterated logarithm for Peng’s estimator [Peng, Stat. Probab. Lett., 52:255–264, 2001] of the mean of heavy-tailed distributions. Our main motivation comes from applications to financial data, and in particular to sequential control of daily asset returns.      

双无限环境中马氏链的强大数定律

在随机环境中马氏链的研究领域 ,构造了一时齐的马氏双链 ,讨论了它的存在性及基本性质 ,最后利用马氏双链的性质 ,得到了双无限环境中马氏链的函数极限定律 ,并给出了该链的函数强大数定律成立的两个充分条件     

0–1 laws for maps

A class of finite structures has a 0–1 law with respect to a logic if every property expressible in the logic has a probability approaching a limit of 0 or 1 as the structure size grows. To formulate 0–1 laws for maps (i.e., embeddings of graphs in a surface), it is necessary to represent maps as logical structures. Three such representations are given, the most general being the full cross representation based on Tutte's theory of combinatorial maps. The main result says that if a class of maps has two properties, richness and large representativity, then the corresponding class of full cross representations has a 0–1 law with respect to first‐order logic. As a corollary the following classes of maps on a surface of fixed type have a first‐order 0–1 law: all maps, smooth maps, 2‐connected maps, 3‐connected maps, triangular maps, 2‐connected triangular maps, and 3‐connected triangular maps. ©1999 John Wiley & Sons, Inc. Random Struct. Alg., 14, 215–237, 1999     

求无穷级数和以及多重积分极限的概率方法

文 [1 ]举例说明了概率思想在求无穷级数的和以及多重积分极限方面的应用 ,本文将对文 [1 ]中的例 1加以推广 ,拓展这一类题的解题思路 ,并对例 2用不同的概率方法加以证明 ,从而使数学分析与概率统计的有关知识联系起来 ,达到知识的融汇贯通 .     

Lyapunov Center Theorem of Infinite Dimensional Hamiltonian Systems

In this paper we reformulate a Lyapunov center theorem of infinite dimensional Hamiltonian systems arising from PDEs. The proof is based on a modified KAM iteration for periodic case.     

19世纪上半叶的无穷级数敛散性判别法

对19世纪上半叶欧洲数学家在正项级数敛散性判别方面的工作作了考察和分析.     

同无限二面体群关联的晶体群的分类

设Ｖ是实数域Ｒ｝上的一个２－维向量空间，Ｖ带有一个仿射的或不定的对称双线性型．无限二面体群Ｗ能够被看作ＧＬ（Ｖ）的一个子群．在本文中，在仿射群Ａ（Ｖ）中共轭的意义下将分类同Ｗ关联的所有晶体群．     

除环上无限方阵的分解

对除环上无限方阵的逆方阵作了简单讨论,证明了除环上无限方阵的分解定理.