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1.
本文将给出k-半分层空间的若干度量化定理以及分导间和σ-空间的度量化定理。  相似文献   

2.
度量空间的k-映射像   总被引:2,自引:0,他引:2  
E.Halfar([6])引入了k-映射概念,本文给出了度量空间k-映像的一个内在刻划,并由此得到一些度量化定理。  相似文献   

3.
关于CWC映射与度量化定理   总被引:1,自引:0,他引:1  
本文讨论CWC映射在度量化定理中的应用, 通过Nagata条件和弱$\gamma$空间条件等给出拓扑空间一些新的度量化定理, 推广了R.E. Hodel和J.Nagata等获得的度量化定理.  相似文献   

4.
度量空间的k—映射像   总被引:3,自引:3,他引:0  
刘川 《数学杂志》1994,14(2):233-236
E.Halfar([6]引入了k-映射概念,本文给出了度量空间k-映像的一个内在刻划,并由此得到一些度量化定理。  相似文献   

5.
K.B.Lee[1]引入了C-分层空间,并研究了它的一些性质,Lee的研究表明C-分层空间是一类具有较好性质的广义度量空间。C-半分层空间在度量化定理中起着重要的作用,例如,正则空间X是可度量化的当且仅当X是C-半分层、WM-空间(见[3])。在本文中,我们讨论C-分层(C-半分层,KC-半分层)空间的映射性质,给出  相似文献   

6.
局部凸H-空间中的Ky Fan型截口定理及其应用   总被引:4,自引:1,他引:3  
沈自飞 《数学进展》2000,29(1):77-82
本文首先在局部凸H-空间中建立一个Fan型截口定理,作为应用,我们H-在空间中获得了相交定理、重合定理和极大极小定理本文中定理把文献中的相应结果改进和推广到H-空间。  相似文献   

7.
建立一种L-Fuzzy命题逻辑的语构分层构造,引进诸如λ-信息,λ-公理系,λ-语构,λ-证明,λ-定理,λ-语构结论,λ-语构闭包,λ-紧性,,上L-Fuzzy语构闭包,下Fuzzy语构闭包,λ-语构分层和谐,语构分层和谐,强语构分层和谐等新的观念和方法,从而L-Fuzzy命题逻辑语构和语义分层次的程度化的和谐性度量提供了一种方案。  相似文献   

8.
张静 《数学研究》2010,43(2):167-170
Frink条件是构造伪度量的关键要求.本文给出Frink条件的一些等价刻画,完善了Gru—enhage论证伪度量存在性的细节,由此给出—致空间度量化定理和Alexandroff-Urysohn度量化定理的简化证明.  相似文献   

9.
向叔文 《数学杂志》1997,17(3):311-314
本文在H-空间的框架下,不依赖于KMM技巧,建立了新的集值映象不动点定理,并且这一结果以赋范空间中的Fan-Glicksberg-Kakutani定理为特例,从而将这一重要定理推至H-空间。  相似文献   

10.
本文在无线性结构H-空间的框架之下给出一个新的von Neumann型非紧极大极小定理,并且作为其应用而得到一个新的Ky Fan型截口定理和一个新的非空交定理.结果即使在欧几里得空间中也是全新的  相似文献   

11.
12.
This paper deals with the notion of residual income, which may be defined as the surplus profit that residues after a capital charge (opportunity cost) has been covered. While the origins of the notion trace back to the 19th century, in-depth theoretical investigations and widespread real-life applications are relatively recent and concern an interdisciplinary field connecting management accounting, corporate finance and financial mathematics (Peasnell, 1981, 1982; Peccati, 1987, 1989, 1991; Stewart, 1991; Ohlson, 1995; Arnold and Davies, 2000; Young and O’Byrne, 2001; Martin, Petty and Rich, 2003). This paper presents both a historical outline of its birth and development and an overview of the main recent contributions regarding capital budgeting decisions, production and sales decisions, implementation of optimal portfolios, forecasts of asset prices and calculation of intrinsic values. A most recent theory, the systemic-value-added approach (also named lost-capital paradigm), provides a different definition of residual income, consistent with arbitrage theory. Enfolded in Keynes’s (1936) notion of user cost and forerun by Pressacco and Stucchi (1997), the theory has been formally introduced in Magni (2000a,b,c; 2001a,b; 2003), where its properties are thoroughly investigated as well as its relations with the standard theory; two different lost-capital metrics have been considered, for value-based management purposes, by Drukarczyk and Schueler (2000) and Young and O’Byrne (2001). This work illustrates the main properties of the two theories and their relations, and provides a minimal guide to construction of performance metrics in the two approaches.  相似文献   

13.
讨论群中两个元素a,b的阶不相等时其乘积ab的阶的一类计算问题.设ㄧaㄧ=m,ㄧ bㄧ=n,若(m,n)=1,且存在k∈N使a=bk,则有ㄧabㄧ=mn/d1d2,其中d1=(m,k+1),d2=(n,k+1).若m≠n,ab=ba,且(m,n)ㄧm/(m,n),或(m,n)ㄧn/(m,n),则有ㄧabㄧ=[m,n].  相似文献   

14.
In this paper, we consider the effect of diffusion on the permanence and extinction of a non-autonomous nonlinear growth rate single-species dispersal model with time delays. Firstly, the sufficient conditions of the permanence and extinction of the species are established, which shows if the growth rate and dispersal coefficients is suitable, the species is permanent, on the contrary, it is extinction. Secondly, an interesting result is established, that is, if only the species in some patches even in one patch is permanent, then it is also permanent in other patches. Finally, some examples together with their numerical simulations show the feasibility of our main results.  相似文献   

15.
The conservation of mass, momentum, energy, helicity, and enstrophy in fluid flow are important because these quantities organize a flow, and characterize change in the flow's structure over time. In turbulent flow, conservation laws remain important in the inertial range of wave numbers, where viscous effects are negligible. It is in the inertial range where energy, helicity (3d), and enstrophy (2d) must be accurately cascaded for a turbulence model to be qualitatively correct. A first and necessary step for an accurate cascade is conservation; however, many turbulent flow simulations are based on turbulence models whose conservation properties are little explored and might be very different from those of the Navier-Stokes equations.We explore conservation laws and approximate conservation laws satisfied by LES turbulence models. For the Leray, Leray deconvolution, Bardina, and Nth order deconvolution models, we give exact or approximate laws for a model mass, momentum, energy, enstrophy and helicity. The possibility of cascades for model quantities is also discussed.  相似文献   

16.
In recent decades, several Multi-Criteria Decision Aid (MCDA) methods have been proposed to help in selecting the best compromise alternatives. In the meantime, the PROMETHEE (Preference Ranking Organization Method for Enrichment Evaluations) family of outranking methods and their applications has attracted much attention from academics and practitioners. In this paper, a classification scheme and a comprehensive literature review are presented in order to uncover, classify, and interpret the current research on PROMETHEE methodologies and applications. Based on the scheme, 217 scholarly papers from 100 journals are categorized into application areas and non-application papers. The application areas include the papers on the topics of Environment Management, Hydrology and Water Management, Business and Financial Management, Chemistry, Logistics and Transportation, Manufacturing and Assembly, Energy Management, Social, and Other Topics. The last area covers the papers published in several fields: Medicine, Agriculture, Education, Design, Government and Sports. The scholarly papers are also classified by (1) year of publication, (2) journal of publication, (3) authors’ nationality, (4) PROMETHEE as applied with other MCDA methods, and (5) PROMETHEE as applied with GAIA (Geometrical Analysis for Interactive Aid) plane. It is hoped that the paper can meet the needs of researchers and practitioners for easy references of PROMETHEE methodologies and applications, and hence promote the future of PROMETHEE research.  相似文献   

17.
A generalization of both the hierarchical product and the Cartesian product of graphs is introduced and some of its properties are studied. We call it the generalized hierarchical product. In fact, the obtained graphs turn out to be subgraphs of the Cartesian product of the corresponding factors. Thus, some well-known properties of this product, such as a good connectivity, reduced mean distance, radius and diameter, simple routing algorithms and some optimal communication protocols, are inherited by the generalized hierarchical product. Besides some of these properties, in this paper we study the spectrum, the existence of Hamiltonian cycles, the chromatic number and index, and the connectivity of the generalized hierarchical product.  相似文献   

18.
根据值域的稠密性和闭性,可将有界线性算子的点谱和剩余谱进一步细分为1,2-类点谱和1,2-类剩余谱.针对3×3阶上三角算子矩阵,采用分析方法和空间分解方法分别刻画了可能1,2-类点谱和可能1,2-类剩余谱.  相似文献   

19.
A variety of continuous-time differential functions have been developed to investigate dynamic advertising problems in business and economics fields. Since major dynamic models appearing before 1995 have been reviewed by a few survey papers, we provide a comprehensive review of the dynamic advertising models published after 1995, which are classified into six categories: (i) Nerlove–Arrow model and its extensions, (ii) Vidale–Wolfe model and its extensions, (iii) Lanchester model and its extensions, (iv) the diffusion models, (v) dynamic advertising-competition models with other attributes, and (vi) empirical studies for dynamic advertising problems. For each category, we first briefly summarize major relevant before-1995 models, and then discuss major after-1995 models in details. We find that the dynamic models reviewed in this paper have been extensively used to analyze various advertising problems in the monopoly, duopoly, oligopoly, and supply chain systems. Our review reveals that the diffusion models have not been used to analyze advertising problems in supply chain operations, which may be a research direction in the future. Moreover, we learn from our review that very few publications regarding dynamic advertising problems have considered the supply chain competition. We also find that very few researchers have used the diffusion model to investigate the dynamic advertising problems with product quality as a decision variable; and, the pricing decision has not been incorporated into any extant Lanchester model. The paper ends with a summary of our review and suggestions on possible research directions in the future.  相似文献   

20.
This work addresses the problem of regularized linear least squares (RLS) with non-quadratic separable regularization. Despite being frequently deployed in many applications, the RLS problem is often hard to solve using standard iterative methods. In a recent work [M. Elad, Why simple shrinkage is still relevant for redundant representations? IEEE Trans. Inform. Theory 52 (12) (2006) 5559–5569], a new iterative method called parallel coordinate descent (PCD) was devised. We provide herein a convergence analysis of the PCD algorithm, and also introduce a form of the regularization function, which permits analytical solution to the coordinate optimization. Several other recent works [I. Daubechies, M. Defrise, C. De-Mol, An iterative thresholding algorithm for linear inverse problems with a sparsity constraint, Comm. Pure Appl. Math. LVII (2004) 1413–1457; M.A. Figueiredo, R.D. Nowak, An EM algorithm for wavelet-based image restoration, IEEE Trans. Image Process. 12 (8) (2003) 906–916; M.A. Figueiredo, R.D. Nowak, A bound optimization approach to wavelet-based image deconvolution, in: IEEE International Conference on Image Processing, 2005], which considered the deblurring problem in a Bayesian methodology, also obtained element-wise optimization algorithms. We show that the last three methods are essentially equivalent, and the unified method is termed separable surrogate functionals (SSF). We also provide a convergence analysis for SSF. To further accelerate PCD and SSF, we merge them into a recently developed sequential subspace optimization technique (SESOP), with almost no additional complexity. A thorough numerical comparison of the denoising application is presented, using the basis pursuit denoising (BPDN) objective function, which leads all of the above algorithms to an iterated shrinkage format. Both with synthetic data and with real images, the advantage of the combined PCD-SESOP method is demonstrated.  相似文献   

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