共查询到20条相似文献,搜索用时 62 毫秒
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正则半群上的矩形群同余 总被引:1,自引:0,他引:1
文[1]中PetrichM定义了同余的核与迹,用它们描述了逆半群上的同余,Gomes在文[2]中定义了同余的核与超迹并描述了正则半群上的R-幂单(R-unipo-tent)同余,本文利用同余的核与超迹描述正则半群上的另一类重要同余,即矩形群同余. 相似文献
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主要讨论π-纯正半群的r-半素矩形群同余和同余对之间的关系,并且找到了在r-半素矩形群同余的集合到r-半素矩形群同余对的集合之间的一一对应. 相似文献
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本将带簇和矩形带簇的概念推广到了n-带簇εn=[x^n 1=x^n]和n-矩形带簇εn=[x^nyx^n=x^n],讨论了这两种半群簇之间的关系,特别对所有n-带簇的并集ε=∪εn和所有n-矩形带簇的并集Rε=∪Rεn进行了研究. 相似文献
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设ρ是半群S上的一个同余,如果S/ρ是矩形带,则称ρ是矩形同余,本文刻画了半群上的最小矩形带同余,设T是半群S的子半群,本文给出了T上每个矩形带同余能扩张成S上矩形带同余的充分必要条件。 相似文献
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本文研究有Clifford断面的纯正半群.为了获得主要的结构定理,证明了纯正半群有群断面当且仅当它是矩形群;利用半格和矩形带,建立了有Clifford断面的纯正半群的结构. 相似文献
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Several results on rectangular products in the sense of B.A. Pasynkov will be obtained, one of which asserts that for a Tychonoff space X, X × Y is rectangular for any space Y iff X is locally compact and paracompact. 相似文献
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Jindřich Zapletal 《Israel Journal of Mathematics》2006,152(1):29-47
I prove forcing preservation theorems for products of definable partial orders preserving cofinality of the meager or null
ideal. Rectangular Ramsey theorems for the related ideals follow from the proofs.
Partially supported by grant GA ČR 201-03-0933, NSF grants DMS 0071437 and DMS 0300201, and a visiting appointment at CRM,
Universitat Autònoma de Barcelona. 相似文献
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Rectangular plates on distributed elastic foundations are widely employed in footings and raft foundations of variety of structures. In particular, mounted columns and single footings may partially occupy the rectangular plate of any kind. 相似文献
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Virginia Naibo 《Journal of Mathematical Analysis and Applications》2006,324(2):834-840
We consider the differentiation of integrals of functions in Besov spaces with respect to the basis of arbitrarily oriented rectangular parallelepipeds in Rn. We study almost everywhere convergence with respect to Bessel capacities. These outer measures are more sensitive than n-dimensional Lebesgue measure, and therefore we improve the positive results in [H. Aimar, L. Forzani, V. Naibo, Rectangular differentiation of integrals of Besov functions, Math. Res. Lett. 9 (2-3) (2002) 173-189]. 相似文献
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Pseudospectra of rectangular matrices 总被引:1,自引:0,他引:1
Pseudospectra of rectangular matrices vary continuously withthe matrix entries, a feature that eigenvalues of these matricesdo not have. Some properties of eigenvalues and pseudospectraof rectangular matrices are explored, and an efficient algorithmfor the computation of pseudospectra is proposed. Applicationsare given in (square) eigenvalue computation (Lanczos iteration),square pseudospectra approximation (Arnoldi iteration), controltheory (nearest uncontrollable system) and game theory. 相似文献
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A Hamiltonian path of a graph is a simple path which visits each vertex of the graph exactly once. The Hamiltonian path problem is to determine whether a graph contains a Hamiltonian path. A graph is called Hamiltonian connected if there exists a Hamiltonian path between any two distinct vertices. In this paper, we will study the Hamiltonian connectivity of rectangular supergrid graphs. Supergrid graphs were first introduced by us and include grid graphs and triangular grid graphs as subgraphs. The Hamiltonian path problem for grid graphs and triangular grid graphs was known to be NP-complete. Recently, we have proved that the Hamiltonian path problem for supergrid graphs is also NP-complete. The Hamiltonian paths on supergrid graphs can be applied to compute the stitching traces of computer sewing machines. Rectangular supergrid graphs form a popular subclass of supergrid graphs, and they have strong structure. In this paper, we provide a constructive proof to show that rectangular supergrid graphs are Hamiltonian connected except one trivial forbidden condition. Based on the constructive proof, we present a linear-time algorithm to construct a longest path between any two given vertices in a rectangular supergrid graph. 相似文献
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陈传淼 《中国科学A辑(英文版)》2003,46(1):1-10
Based on an orthogonal expansion and orthogonality correction in an element, superconvergence at symmetric points for any degree rectangular serendipity finite element approximation to second order elliptic problem is proved, and its behaviour up to the boundary is also discussed. 相似文献
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Katsunori Tani Shuji Tsukiyama Shoji Shinoda Isao Shirakawa 《Mathematical Programming》1991,52(1-3):29-43
In this paper, we consider a problem to seek a rectangular dual
and its area-efficient drawing such that
can be drawn in the smallest area among all rectangular duals under the constraints imposed not only on the area and the minimum dimension of each face but also on the length of abutment between two adjacent faces. Since the problem is hard to solve, we tackle this problem in an exhaustive manner by using an algorithm to enumerate all the rectangular duals. In order to make this exhaustive method efficient, we propose the following two algorithms working under the constraints stated above; an algorithm to find an area-efficient drawing of a given rectangular dual, and an algorithm to estimate a lower bound to the area required to draw a given rectangular dual. We also show some esperimental results to demonstrate the effectiveness of the lower bound. The area-efficient drawing of
can be used as a VLSI floor-plan by regarding each inner face of
as an area for a block to be placed. 相似文献
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The real rectangular tensors arise from the strong ellipticity condition problem in solid mechanics and the entanglement problem
in quantum physics. Some properties concerning the singular values of a real rectangular tensor were discussed by K. C. Chang
et al. [J. Math. Anal. Appl., 2010, 370: 284–294]. In this paper, we give some new results on the Perron-Frobenius Theorem
for nonnegative rectangular tensors. We show that the weak Perron-Frobenius keeps valid and the largest singular value is
really geometrically simple under some conditions. In addition, we establish the convergence of an algorithm proposed by K.
C. Chang et al. for finding the largest singular value of nonnegative primitive rectangular tensors. 相似文献
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《Optimization》2012,61(7):989-1002
The rectangular packing problem aims to seek the best way of placing a given set of rectangular pieces within a large rectangle of minimal area. Such a problem is often constructed as a quadratic mixed-integer program. To find the global optimum of a rectangular packing problem, this study transforms the original problem as a mixed-integer linear programming problem by logarithmic transformations and an efficient piecewise linearization approach that uses a number of binary variables and constraints logarithmic in the number of piecewise line segments. The reformulated problem can be solved to obtain an optimal solution within a tolerable error. Numerical examples demonstrate the computational efficiency of the proposed method in globally solving rectangular packing problems. 相似文献