Boolean Hierarchies of Partitions over a Reducible Base

The Boolean hierarchy of partitions was introduced and studied by Kosub and Wagner, primarily over the lattice of NP-sets. Here, this hierarchy is treated over lattices with the reduction property, showing that it has a much simpler structure in this instance. A complete characterization is given for the hierarchy over some important lattices, in particular, over the lattices of recursively enumerable sets and of open sets in the Baire space.     

Integral Representations for Correlation Functions of the XXZ Heisenberg Chain

We consider new integral representations for two-point correlation functions of local spins 1/2 in the XXZ Heisenberg chain.     

2+1维SU(2)格点规范场胶球质量的无规相近似计算

采用无规相近似(RPA)耦合集团展开方法,用空心图作为试探波函数,利用Feymann-Hellman定理和截断薛定谔方程本征值方程的方法得到的封闭方程组,计算出三到六阶2+1维SU(2)格点规范场的胶球质量.结果显示:当计算进行到六阶时,胶球质量已出现标度窗口和收敛趋势,预示七阶结果将在弱耦合区能表现出良好的标度行为和收敛性     

Kosterlitz-Thouless transition for the finite-temperatured=2+1,U(1) Hamiltonian lattice gauge theory

We prove that in thed=2+1,U(1) Hamiltonian (continuous time) lattice gauge theory the confining potential between two static external charges grows logarithmically with their distance, at sufficiently high temperatures. As it is known that for zero or low temperatures and large coupling constant the model confines linearly, we have therefore established the existence of a Kosterlitz-Thouless transition. Our results are based on a Mermin-Wagner type of argument combined with correlation inequalities and known results for the two-dimensional (spin) Villain model.     

The random parking problem

A new approach to the random parking problem is given.     

分子格半群

在本文中，作者在格半群上引入了半群元和理想元的概念，使得半群（理想）和ＴＬ－Ｆｕｚｚｙ半群（理想）是其特例。在分子格半群上引入了群元和正规群元等概念，在更高的层次上统一了群和Ｌ－Ｆｕｚｚｙ群。     

Global invariants and equilibrium states in lattice gases

It is now well known that, in addition to the physical conserved quantities, lattice gases also have other unphysical ones related to the discretization of their phase space. From an abstract point of view a lattice gas can be considered like a full discrete Markov processL and these spurious conserved quantities yield the existence of a nonspatially homogeneous equilibrium state forL ^k. We show that a particular set of these conserved quantities is of special interest: Its elements will be called regular. These regular invariants are simply built from the local ones and their projection on each node is always a locally conserved quantity. Moreover, for most models they are one-to-one related to the Gibbs states ofL ^k which remain factorized. It turns out that all the classical known spurious invariants are regular and one can exhibit simple conditions to build models with only regular invariants. For the latter it is then justified to determine the transport coefficients of the locally conserved densities with the Green-Kubo procedure.     

Lorentz lattice gases: Basic theory

We present several ballistic models of the Lorentz gas in two-dimensional lattices with deterministic and stochastic deflection rules, and their corresponding Liouville equations. Boltzmann-level-equation results are obtained for the diffusion coefficient and velocity autocorrelation function for models with stochastic deflection rules. The long-time behavior of the mean square displacement is briefly discussed and the possibility of abnormal diffusion indicated. Even if the diffusion coefficient exists, its low-density limit may not be given correctly by the Boltzmann equation.     

完全分配格上的良Urysohn性

本文目的是在无逆序对合的分配格上研究余拓扑的Urysohn性质，利用coHeyting代数的pseudo-negation和分子的linked component的概念，在完全分配格上定义了一种新的Urysohn性质，称之为良Urysohn性．文中详细地讨论良Urysohn性的基本性质，并利用文中建立的Urysohn收敛理论给出了良Urysohn性的刻画定理．