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1.
Giuseppe Peano's development of the real number system from his postulates for the natural numbers and some of his views on definitions in mathematics are presented in order to clarify his concept of number. They show that his use of the axiomatic method was intended to make mathematical theory clearer, more precise, and easier to learn. They further reveal some of his reasons for not accepting the contemporary “philosophies” of logicism and formalism, thus showing that he never tried to found mathematics on anything beyond our experience of the material world.  相似文献   

2.
《Journal of Complexity》2004,20(5):699-712
The computation of combinatorial and numerical problems on quantum computers is often much faster than on a classical computer in numbers of queries. A query is a procedure by which the quantum computer gains information about the specific problem. Different query definitions were given and our aim is to review them and to show that these definitions are not equivalent. To achieve this result we will study the simulation and approximation of one query type by another. While approximation is “easy” in one direction, we will show that it is “hard” in the other direction by a lower bound for the numbers of queries needed in the simulation. The main tool in this lower bound proof is a relationship between quantum algorithms and trigonometric polynomials that we will establish.  相似文献   

3.
对属性值为区间数的多属性决策问题,采用Vague集方法进行处理.首先利用区间数决策矩阵的规范化把区间评价值转化为Vague值,然后利用Vague集方法对方案进行排序并选出最优方案.实例分析阐明了本文方法的有效性和实用性.  相似文献   

4.
I.M. James 《Topology》1978,17(4):331-348
In the course of research into the calculus of variations, a new numerical topological invariant was introduced by Lusternik and Schnirelmann[26] and shown to give important information about the existence of critical points. This invariant, the category of a space, has received a great deal of study over the years and it seems time for a fairly comprehensive review. While it is impossible to include everything, for reasons of space, I have tried to say something about each of the different viewpoints and, wherever possible, to give sketch proofs of some characteristic results, with appropriate illustrations. This work has been much improved following the suggestions of Dr. Wilhelm Singhof who kindly read an early draft. I am most grateful to him and to others who have helped with particular points.  相似文献   

5.
There are three general lower bound techniques for the crossing numbers of graphs, all of which can be traced back to Leighton's work on applications of crossing number in VLSI: the Crossing Lemma, the Bisection Method, and the Embedding Method. In this contribution, we sketch their adaptations to the minor crossing number.  相似文献   

6.
A step‐stress accelerated life testing model is considered for progressive type‐I censored experiments when the tested items are not monitored continuously but inspected at prespecified time points, producing thus grouped data. The underlying lifetime distributions belong to a general scale family of distributions. The points of stress‐level change are simultaneously inspection points as well while there is the option of assigning additional inspection points in between the stress‐level change points. In a Bayesian framework, the posterior distributions of the parameters of the model are derived for characteristic choices of prior distributions, as conjugate‐like and normal priors; vague or noninformative. The developed approach is illustrated on a simulated example and on a real data set, both known from the literature. The results are compared to previous analyses; frequentist or Bayes.  相似文献   

7.
"无穷小的比较"的现有定义有多种表述形式,但其中不少表述尚不够准确,有失严谨,甚至会导致错误命题的出现.引入"基"概念可使无穷小及无穷小比较的定义更为严谨、简洁、一般化.将无穷小量按含O值点的不同情况分为2类,有利于找出"无穷小的比较"现有定义中存在的问题.通过调整大前提,解决了定义项与被定义项外延不一致的问题;通过转...  相似文献   

8.
In this paper, we address linear bilevel programs when the coefficients of both objective functions are interval numbers. The focus is on the optimal value range problem which consists of computing the best and worst optimal objective function values and determining the settings of the interval coefficients which provide these values. We prove by examples that, in general, there is no precise way of systematizing the specific values of the interval coefficients that can be used to compute the best and worst possible optimal solutions. Taking into account the properties of linear bilevel problems, we prove that these two optimal solutions occur at extreme points of the polyhedron defined by the common constraints. Moreover, we develop two algorithms based on ranking extreme points that allow us to compute them as well as determining settings of the interval coefficients which provide the optimal value range.  相似文献   

9.
基于Vague集的模糊多目标决策方法及应用   总被引:1,自引:0,他引:1  
针对目前基于Vague集多目标决策中Vague值计算困难以及确定目标满意度的下界和不满意度的上界存在主观随意性问题.提出了一种基于Vague集的模糊多目标决策方法.利用属性数学中的属性集和属性测度理论构造目标的真隶属度函数、假隶属度函数和犹豫度函数,从而可计算出目标的Vague值;采用记分函数计算方案的多目标评分值,从而可以对方案进行排序并选择出最优方案.应用实例验证了该方法的有效性和实用性.  相似文献   

10.
This work proposes an upper bound on the maximal number of non-dominated points of a multicriteria optimization problem. Assuming that the number of values taken on each criterion is known, the criterion space corresponds to a comparability graph or a product of chains. Thus, the upper bound can be interpreted as the stability number of a comparability graph or, equivalently, as the width of a product of chains. Standard approaches or formulas for computing these numbers are impractical. We develop a practical formula which only depends on the number of criteria. We also investigate the tightness of this upper bound and the reduction of this bound when feasible, possibly efficient, solutions are known.  相似文献   

11.
This paper considers two “mysteries” having to do with vagueness. The first pertains to existence. An argument is presented for the following conclusion: there are possible cases in which ‘There exists something that is F’ is of indeterminate truth-value and with respect to which it is not assertable that there are borderline-cases of “being F.” It is contended that we have no conception of vagueness that makes this result intelligible. The second mystery has to do with “ordinary” vague predicates, such as ‘tall’. An argument is presented for the conclusion that although there are people who are “tall to degree 1”—definitely tall, tall without qualification—, no greatest lower bound can be assigned to the set of numbers n such that a man who is n centimeters tall is tall to degree 1. But, since this set is bounded from below, this result seems to contradict a well-known property of the real numbers.  相似文献   

12.
13.
一种Vague偏好群体决策方法   总被引:2,自引:0,他引:2  
采用 Vague集理论来描述和处理不确定信息或含糊信息 ,比采用模糊集理论描述和处理不确定信息或含糊信息在很多情况下更贴近客观现实 .在诸学者对模糊群体决策研究的基础上 ,提出一种 Vague群体决策方法 ,采用 Vague值作为决策者对备选方案的评估值 ,通过对决策者的各备选方案偏好值的集结 ,最后根据集结值的效用值对备选方案排序 ,进行决策 .  相似文献   

14.
引入了区别于现有文献的Vague集信息熵和Vague集的关联熵的概念,给出了一种改进的测量方法,并讨论了它们之间的关系。进而,我们揭示了Vague集的熵和Fuzzy集的熵之间的关系,并分析了本文所定义熵的意义。最后,讨论了这种关联熵在模糊识别和医疗诊断上的应用。  相似文献   

15.
Summary It is shown that there is a positive lower bound,c, to the uniform error in any scheme designed to recover all functions of a certain smoothness from their values at a fixed finite set of points. This lower bound is essentially attained by interpolation at the points by splines with canonical knots. Estimates ofc are also given.  相似文献   

16.
17.
In this paper, multi-objective models for designing 3D trajectory of horizontal wells are developed in a fuzzy environment. Here, the objectives of minimizing the length of the trajectory and the error of entry target point are fuzzy in nature. Some parameters, such as initial value, end value, lower bound and upper bound of the curvature radius, tool-face angle and the are length of each curve section, are also assumed to be vague and imprecise. The impreciseness in the above objectives have been expressed by fuzzy linear membership functions and that in the above parameters by triangular fuzzy numbers. Models have been solved by the fuzzy non-linear programming method based on Zimmermann [1] and Lee and Li [2]. Models are applied to practical design of the horizontal wells. Numerical results illustrate the accuracy and efficiency of the fuzzy models.  相似文献   

18.
Barry Lam 《Acta Analytica》2013,28(3):359-379
What is the proper attitude toward what is expressed by a vague sentence in the face of borderline evidence? Some call this attitude “ambivalence” and distinguish it from uncertainty. It has been argued that Classical Epistemicism conjoined with classical probability theory fails to characterize this attitude, and that we must therefore abandon classical logic or classical probabilities in the presence of vagueness. In this paper, I give a characterization of ambivalence assuming a supervaluationist semantics for vague terms that does not revise either. The theory, which I call the theory of Superprobabilities, identifies the proper attitude toward a vague sentence, in the presence of exact borderline evidence, as the set of classical probabilities of the evidence on each member of the set of all precisifications of a vague sentence. I defend the use of sets of probabilities against objections by generalizing the theory of Superprobabilities to a decision theory called Superrationality. I then compare the merits of the theory of Superprobabilities to Classical Epistemicism and nonclassical probabilities theories with respect to the problem of ambivalence.  相似文献   

19.
Much attention has been given to the question of ontic vagueness, and the issues usually center around whether certain paradigmatically concrete entities - cats, clouds, mountains, etc. - are vague in the sense of having indeterminate spatial boundaries. In this paper, however, I wish to focus on a way in which some abstracta seem to be locationally vague. To begin, I will briefly cover some territory already covered regarding certain types of “traditional” abstracta and the ways they are currently alleged to be vague. I then wish to discuss two types of “nontraditional” abstracta and the sense in which I think some of these objects are locationally vague. I will next reexamine some of the traditional abstracta and discuss whether any of these objects are locationally vague in the novel way suggested for the nontraditional sorts. I’ll finish by discussing objections, and conclude with some remarks about characterizing the abstract/concrete distinction.  相似文献   

20.
零误差计算     
研究采用有误差的数值计算来获得无误差的准确值具有重要的理论价值和应用价值.这种通过近似的数值方法获得准确结果的计算被称为零误差计算.本文首先指出,只有一致离散集合中的数才能够开展零误差计算,即有非零隔离界的数集,这也是"数"可以进行零误差计算的一个充要条件.以此为基本出发点,本文分析代数数零误差计算的最低理论精度,该精度对应于恢复近似代数数的准确值时必要的误差控制条件,但由于所采用恢复算法的局限性,这一理论精度往往不能保证成功恢复出代数数的准确值.为此,本文给出采用PSLQ (partial-sum-LQ-decomposition)算法进行代数数零误差计算所需的精度控制条件,与基于LLL (Lenstra-Lenstra-Lovász)算法相比,该精度控制条件关于代数数次数的依赖程度由二次降为拟线性,从而可降低相应算法的复杂度.最后探讨零误差计算未来的发展趋势.  相似文献   

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