复合源模糊数及其运算

指出在多模糊源情况下采用多元扩张原理进行模糊数运算中存在的问题,定义复合源模糊数的一些基本概念,并建立在复合源直接模糊数与单源直接模糊数间的乘除运算方法,给出复合源模糊数线性方程组的求解方法。     

单源模糊数及其运算

本文首先指出模糊数的运算存在模糊源问题，然后定义了单源模糊数的一些基本概念，并建立了单源模糊数的运算方法，最后给出了单源模糊数线性方程组的求解方法。     

Shifting Operations and Graded Betti Numbers

The behaviour of graded Betti numbers under exterior and symmetric algebraic shifting is studied. It is shown that the extremal Betti numbers are stable under these operations. Moreover, the possible sequences of super extremal Betti numbers for a graded ideal with given Hilbert function are characterized. Finally it is shown that over a field of characteristic 0, the graded Betti numbers of a squarefree monomial ideal are bounded by those of the corresponding squarefree lexsegment ideal.     

Ordinal Operations on Surreal Numbers

An open problem posed by John H. Conway in [2] was whether onecould, on his system of numbers and games, ‘... defineoperations of addition and multiplication which will restricton the ordinals to give their usual operations’. Sucha definition for addition was later given in [4], and this paperwill show that a definition also exists for multiplication.An ordinal exponentiation operation is also considered.     

圆楔形模糊复数及其运算

运用模糊复集合的基本理论,给出圆楔形模糊复数的定义,并研究了有界圆楔形闭模糊复数的性质及其基本运算。     

Fuzzy数的扩张运算及其性质

本文讨论了Ｆ数的扩张加法和扩张数乘运算的性质；并举反例说明这样的扩张运．算不能使Ｆ数全体Ｆ＊构成线性空间；最后对可列个Ｆ数的运算进行了讨论．     

基于结构元的复模糊数四则运算

运用模糊数的模糊结构元表述理论,引入了区间[-1,1]上单调函数的某些同序单调变换,将复模糊数的加、减、乘、除运算转换为同序单调函数之间的相应运算.解决了以往基于扩张原理运算中的遍历过程带来的极大不便.同时,讨论了模糊结构元线性生成的复模糊数及其运算.     

Polar SAT and related graphs

We introduce polar SAT and show that a general SAT can be reduced to it in polynomial time. A set of clauses C is called polar if there exists a partition C^pCⁿ=C, called a polar partition, such that each clause in C^p involves only positive (i.e., non-complemented) variables, while each clause in Cⁿ contains only negative (i.e., complemented) variables. A polar set of clauses C=(C^p,Cⁿ) is called (p,n)-polar, where p1 and n1, if each clause in C^p (respectively, in Cⁿ) contains exactly p (respectively, exactly n) literals. We classify all (p,n)-polar SAT Problems according to their complexity. Specifically, a (p,n)-Polar SAT problem is NP-complete if either p>n2 or n>p2. Otherwise it can be solved in polynomial time. We introduce two new hereditary classes of graphs, namely polar satgraphs and polar (3,2)-satgraphs, and we characterize them in terms of forbidden induced subgraphs. Both characterization involve an infinite number of minimal forbidden induced subgraphs. As are result, we obtain two narrow hereditary subclasses of weakly chordal graphs where Independent Domination is an NP-complete problem.     

SAT:Algebra and Functions

1. Frank＇s gas tank was 1/4full. After put ting in G gallons of gasoline, the tank was 5/6full. What was the capacity of the tank.     

Operations and Spectral Sequences. I

Using methods developed by W. Singer and J. P. May, we describe a systematic approach to showing that many spectral sequences, determined by a filtration on a complex whose homology has an action of operations, possess a compatible action of the same operations. As a consequence, we obtain W. Singer's result for Steenrod operations on Serre spectral sequence and extend A. Bahri's action of Dyer-Lashof operations on the second quadrant Eilenberg-Moore spectral sequence.

     

The state of SAT

The papers in this special issue originated at SAT 2001, the Fourth International Symposium on the Theory and Applications of Satisfiability Testing. This foreword reviews the current state of satisfiability testing and places the papers in this issue in context.     

Semistar Operations and Standard Closure Operations

Let R be a commutative ring. It is shown that there is an order isomorphism between a popular class of finite type closure operations on the ideals of R and the poset of semistar operations of finite type.     

[-1,1]上同序单调函数的同序变换群与模糊数运算

定义对称区间[-1,1]上的同序单调有界函数的同序变换,利用文[1]提出的模糊数的结构元表示方法,得到模糊数四则运算的结构元表示以及模糊数运算结果的隶属函数的确定方法。在多数的模糊数运算问题中,结构元的单调变换形式是容易得到的,此时,模糊数的运算将变得非常简单。文中还给出了一个运算的实例。     

Curriculum-based course timetabling with SAT and MaxSAT

This paper describes our work on applying novel techniques based on propositional satisfiability (SAT) solvers and optimizers to the Curriculum-based Course Timetabling problem. Out of 32 standard benchmark instances derived from the Second International Timetabling Competition held in 2007, our techniques yield the best known solutions for 21 of them (19 of them being optimal), improving the previously best known solutions for 9. In addition, we obtain 18 new lower bounds for this benchmark set by applying a new full (Weighted) Partial MaxSAT approach of the Curriculum-based Course Timetabling problem.