关于BCI—代数伴随半群中的可逆元

给出了ＢＣＩ－代数的伴随半群中可逆元的刻划，说明ＢＣＩ－代数的ｐ－半单闭理想与其伴随半群的子群之间有一一对应关系，并证明最大的ｐ－半单闭理想是根理想。     

Branching/queueing networks: Their introduction and near-decomposability asymptotics

A new class of models, which combines closed queueing networks with branching processes, is introduced. The motivation comes from MIMD computers and other service systems in which the arrival of new work is always triggered by the completion of former work, and the amount of arriving work is variable. In the variant of branching/queueing networks studied here, a customer branches into a random and state-independent number of offspring upon completing its service. The process regenerates whenever the population becomes extinct. Implications for less rudimentary variants are discussed. The ergodicity of the network and several other aspects are related to the expected total number of progeny of an associated multitype Galton-Watson process. We give a formula for that expected number of progeny. The objects of main interest are the stationary state distribution and the throughputs. Closed-form solutions are available for the multi-server single-node model, and for homogeneous networks of infinite-servers. Generally, branching/queueing networks do not seem to have a product-form state distribution. We propose a conditional product-form approximation, and show that it is approached as a limit by branching/queueing networks with a slowly varying population size. The proof demonstrates an application of the nearly complete decomposability paradigm to an infinite state space. This revised version was published online in June 2006 with corrections to the Cover Date.     

The Closed Subsemigroups of a Clifford Semigroup

In this paper we study the closed subsemigroups of a Clifford semigroup. shown that{∪- αεY＇ Gα, [ Y＇ ε P（Y）} is the set of all closed subsemigroups of It is a Clifford semigroup S = {Y; Gα; Фα,β}, where Y＇- denotes the suhsemilattice of Y generated by Y＇. In particular, G is the only dosed subsemigroup of itself for a group G and each one of subsemilattiees of a semilattiee is closed. Also, it is shown that the semiring P（S） is isomorphic to the semiring P（Y） for a Clifford semigroup S = [Y; Gα; Фα,β].     

Synchronism of an incompressible non-free Seifert surface for a knot and an algebraically split closed incompressible surface in the knot complement

We give a necessary and sufficient condition for knots to bound incompressible non-free Seifert surfaces.

     

Properties of the Absolute That Affect Smoothness of Flows on Closed Surfaces

Let be a closed orientable surface of genus , endowed with the structure of a Riemann manifold of constant negative curvature. For the universal covering , there is the notion of absolute, each of whose points determines an asymptotic direction of a bundle of parallel equidirected geodesics. In the paper it is proved that there is a set on the absolute having the cardinality of the continuum and such that if an arbitrary flow on has a semitrajectory whose covering has asymptotic direction defined by a point from , then this flow is not analytical and has infinitely many stationary points.     

Closed polling models with failing nodes

Closed polling systems with station breakdowns, under the gated, exhaustive or globally gated services regimes, are studied and analyzed. Multi-dimensional sets of probability generating functions of the system's state are derived. They are further utilized to obtain an approximate solution for the mean number of jobs residing in the system's various queues at polling instants. The analysis is then concentrated on the case of cyclic Bernoulli polling. Explicit formulae for the mean number of jobs, as well as for the expected cycle duration and system utilization, are derived. Comparison of the throughputs of the three regimes concludes the paper. This revised version was published online in June 2006 with corrections to the Cover Date.     

水泥强度的模糊预测模型研究

本文根据水泥强度的模糊性 ,运用模糊模式识别理论 ,建立了预测水泥强度的模糊贴近度模型 .通过对上海水泥厂提供的实测数据进行模糊计算 ,得到了令人满意的结果 ,为水泥强度的快速预测提供了一种新方法 ,有较好的实用价值 .     

关于KKM映射的一点注记

在超凸度量空间中讨论了一类较广的KKM映射的性质，并以此推断出Fan—Browder型不动点定理。所得结果统一并推广了[5—6]中某些结果。