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．     

New relationships between steenrod operations for certain spaces

In this paper, we show that under a certain technical condition, if a space has no 2-torsion, then eitherS q ² n x≠0 or there exists somey withS q ² n y=S q ² n ⁺¹ x, if for somen≥3S q ² n ⁺¹ x≠0. The proof uses relations between Steenrod operations and operations in connective realK-Theory. This research was partially supported by NSERC.     

Symmetric operations in algebraic cobordism

In this article we describe certain new cohomological operations in algebraic cobordisms. These operations give the natural obstructions for the cobordism class to be represented by the embedding. Also, they permit to work with algebraic cobordisms and Chow groups in a more subtle way than the Landweber-Novikov operations (related to 2-torsion effects). We describe applications to the computation of the algebraic cobordisms of a Pfister quadrics and to the problem of rationality of cycles.     

A complete characterization of exponential stability for discrete dynamics

For a discrete dynamics defined by a sequence of bounded and not necessarily invertible linear operators, we give a complete characterization of exponential stability in terms of invertibility of a certain operator acting on suitable Banach sequence spaces. We connect the invertibility of this operator to the existence of a particular type of admissible exponents. For the bounded orbits, exponential stability results from a spectral property. Some adequate examples are presented to emphasize some significant qualitative differences between uniform and nonuniform behaviour.     

The unstable integral homology of the mapping class groups of a surface with boundary

We construct a graph complex calculating the integral homology of the bordered mapping class groups. We compute the homology of the bordered mapping class groups of the surfaces S _1,1, S _1,2 and S _2,1. Using the circle action on this graph complex, we build a double complex and a spectral sequence converging to the homology of the unbordered mapping class groups. We compute the homology of the punctured mapping class groups associated to the surfaces S _1,1 and S _2,1. Finally, we use Miller’s operad to get the first Kudo–Araki and Browder operations on our graph complex. We also consider an unstable version of the higher Kudo–Araki–Dyer–Lashoff operations.     

矩阵乘积的初等变换术及其应用

通过矩阵乘法运算的拆行拆列表示,巧妙地绕过初等矩阵,建立了矩阵乘积的初等变换术,进而导出了原来运用初等矩阵才能导出的有关初等变换、逆矩阵、矩阵方程、矩阵等价的若干重要结果.     

Vector subspaces of finite fields and star operations on pseudo-valuation domains

Given an extension of finite fields $F\subseteq L$, we study the number of the equivalence classes of F-vector subspaces of L modulo multiplication by elements of L, obtaining an exact formula and some bounds. We then apply the results obtained to the study of the set of F-star operations on L, which correspond to star operations on a pseudo-valuation domain R.     

Free continuous actions on zero-dimensional spaces

We show that every countably infinite group admits a free, continuous action on the Cantor set having an invariant probability measure. We also show that every countably infinite group admits a free, continuous action on a non-homogeneous compact metric space and the action is minimal (that is to say, every orbit is dense). In answer to a question posed by Giordano, Putnam and Skau, we establish that there is a continuous, minimal action of a countably infinite group on the Cantor set such that no free continuous action of any group gives rise to the same equivalence relation.     

Games,Kernels, and Antitone Operations

In this note we want to point out the usefulness of antitone operations in the study of games on graphs. We demonstrate this by proving, among others, the generalizations from games to antitone operations of theorems stated by Fraenkel. This perspective makes also clear the general nature of some problems by separating what is general and what is particular.     

Torsion in the cohomology of finite loop spaces and the Eilenberg–Moore spectral sequence

We use the Eilenberg–Moore spectral sequence to study torsion phenomena in the integral cohomology of finite loop spaces with maximal torus generalizing some results for compact Lie groups due to Kac.     

The eye and the fist: Optimizing search and interdiction

Interdiction operations involving search, identification, and interception of suspected objects are of great interest and high operational importance to military and naval forces as well as nation’s coast guards and border patrols. The interdiction scenario discussed in this paper includes an area of interest with multiple neutral and hostile objects moving through this area, and an interdiction force, consisting of an airborne sensor and an intercepting surface vessel or ground vehicle, whose objectives are to search, identify, track, and intercept hostile objects within a given time frame. The main contributions of this paper are addressing both airborne sensor and surface vessel simultaneously, developing a stochastic dynamic-programming model for optimizing their employment, and deriving operational insight. In addition, the search and identification process of the airborne sensor addresses both physical (appearance) and behavioral (movement pattern) signatures of a potentially hostile object. As the model is computationally intractable for real-world scenarios, we propose a simple heuristic policy, which is shown, using a bounding technique, to be quite effective. Based on a numerical case study of maritime interdiction operations, which includes several representative scenarios, we show that the expected number of intercepted hostile objects, following the heuristic decision policy, is at least 60% of the number of hostile objects intercepted following an optimal decision policy.     

Exterior power operations on higher K-theory

We construct operations on higher algebraic K-groups induced by operations such as exterior power on any suitable exact category, without appeal to the plus-construction of Quillen.Dedicated to Alexander Grothendieck on his sixtieth birthdaySupported by NSF grants DMS 85-04692, 86-01980.     

Adams operations on higherK-theory

We construct Adams operations on higher algebraicK-groups induced by operations such as symmetric powers on any suitable exact category, by constructing an explicit map of spaces, combinatorially defined. The map uses theS-construction of Waldhausen, and deloops (once) earlier constructions of the map.Supported by NSF grant DMS 90-02715     

Zimbabwean in-service mathematics teachers’ understanding of matrix operations

In Zimbabwe, school pupils study matrix operations, a topic that is usually covered as part of linear algebra courses taken by most mathematics undergraduate students at university. In this study we focused on Zimbabwean teachers who were studying the topic at university while also teaching the topic to their high school pupils. The purpose of the study was to explore the mental conceptions of matrix operations concepts of a sample of 116 in-service mathematics teachers. The Action Process Object Schema (APOS) theoretical framework describes the development in understanding of mathematics concepts through the hierarchical growth of mental constructions called action, process, object and schema. The results showed that many of the participants had interiorized actions on matrix operations of addition, scalar multiplication and matrix multiplication into processes. However, more than 50% of the participants struggled with scalar multiplication of a row matrix by a column matrix. In terms of notational errors, some participants could not distinguish between brackets that denote a matrix and that of a determinant, while some used the equal sign as an operator symbol and not as one denoting equivalence between two objects. It is recommended that future in-service teacher programs should try to create more structured opportunities to allow participants to engage more deeply with these concepts.     

Stabilized rounded addition of hierarchical matrices

The efficiency of hierarchical matrices is based on the approximate evaluation of usual matrix operations. The introduced approximation error may, however, lead to a loss of important matrix properties. In this article we present a technique which preserves the positive definiteness of a matrix independently of the approximation quality. The importance of this technique is illustrated by an elliptic mixed boundary value problem with tiny Dirichlet part. Copyright © 2007 John Wiley & Sons, Ltd.     

Patterns of simple gene assembly in ciliates

The intramolecular model for gene assembly in ciliates considers three operations, , , and that can assemble any gene pattern through folding and recombination: the molecule is folded so that two occurrences of a pointer (short nucleotide sequence) get aligned and then the sequence is rearranged through recombination of pointers. In general, the sequence rearranged by one operation can be arbitrarily long and consist of many coding and noncoding blocks. We consider in this paper simple variants of the three operations, where only one coding block is rearranged at a time. We characterize in this paper the gene patterns that can be assembled through these variants. Our characterization is in terms of signed permutations and dependency graphs. Interestingly, we show that simple assemblies possess rather involved properties: a gene pattern may have both successful and unsuccessful assemblies and also more than one successful assembling strategy.     

Computing the eccentric-distance sum for graph operations

In this paper, we present explicit formulas for computing the eccentric-distance sum of the most important graph operations such as the Cartesian product, join, composition, disjunction, symmetric difference, cluster and corona product of graphs. Also, we apply our results to compute this eccentricity-related invariant for some important classes of molecular graphs and nano-structures by specializing components of these graph operations.     

Towards a classification of stable semistar operations on a Prüfer domain

We study stable semistar operations defined over a Prüfer domain, showing that, if every ideal of a Prüfer domain R has only finitely many minimal primes, every such closure can be described through semistar operations defined on valuation overrings of R.     

交换的实W~*-代数

本文指出，交换的（复）Ｗ 代数的大部分结果对于实情形仍然成立，自然有周期为２同胚的差别．此外，不同于复情形，可分实Ｈｉｌｂｅｒｔ空间中不包含任何极小投影的交换实ＶＮ代数同构于Ｌ∞（［０，１］），Ｌ∞ｒ（［０，１］）或Ｌ∞（［０，１］）Ｌ∞ｒ（［０，１］）．     

On the Topology of Fibrations with Section and Free Loop Spaces

We relate the brace products of a fibration with section tothe differentials in its Serre spectral sequence. In the particularcase of free loop fibrations, we establish a link between thesedifferentials and Browder operations in the fiber. Applicationsand several calculations (for the particular cases of spheresand wedges of spheres) are given. 2000 Mathematical SubjectClassification: 55P35, 55Q15, 55R05, 55R20.