共查询到20条相似文献,搜索用时 31 毫秒
1.
Andrzej Mróz 《代数通讯》2013,41(6):2005-2036
Let Λ be the four subspace algebra. We show that for any Λ-module M there exists an algorithm (up to the problem of finding roots of the so-called characteristic polynomial of M) with relatively low polynomial complexity of determining multiplicities of all direct summands of M. Moreover, we give a fully algorithmic criterion for deciding if two Λ-modules M and N are isomorphic. 相似文献
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We study the moment problem in a complex domain. The results obtained generalize and sharpen the well-known Kaz'min result. We also consider applications of these results to the Abel--Goncharov problem (the uniqueness and construction problem) and to the completeness problem for systems of analytic functions. 相似文献
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Motivated by dead-mileage problem assessed in terms of running empty buses from various depots to starting points, we consider a class of the capacitated transportation problems with bounds on total availabilities at sources and total destination requirements. It is often difficult to solve such problems and the present paper establishes their equivalence with a balanced capacitated transportation problem which can be easily solved by existing methods. Sometimes, total flow in transportation problem is also specified by some external decision maker because of budget/political consideration and optimal solution of such problem is of practical interest to the decision maker and has motivated us to discuss such problem. Various situations arising in unbalanced capacitated transportation problems have been discussed in the present paper as a particular case of original problem. In addition, we have discussed paradoxical situation in a balanced capacitated transportation problem and have obtained the paradoxical solution by solving one of the unbalanced problems. Numerical illustrations are included in support of theory. 相似文献
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讨论确定Sturm-Liouville问题中算子的系数α(x)或者q(x)的问题.在一定条件下,系数α(x)或者q(x)可由数据或者数据唯一确定,这里的uj(x)满足而构成L2(0,1)的一个基,α和β为给定的实数. 相似文献
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Valeria Leggieri Paolo Nobili Chefi Triki 《Mathematical Methods of Operations Research》2008,68(2):295-311
In this paper we deal with the minimum power multicasting (MPM) problem in wireless ad-hoc networks. By using an appropriate
choice of the decision variables and by exploiting the topological properties of the problem, we are able to define an original
formulation based on a Set Covering model. Moreover, we propose for its solution two exact procedures that include a preprocessing
technique that reduces the huge number of the model’s constraints. We also report some experimental results carried out on
a set of randomly generated test problems. 相似文献
8.
Anastasios Zachos Athanase Cotsiolis 《Journal of Mathematical Analysis and Applications》2011,373(1):44-58
We study the weighted Fermat-Torricelli (w.F-T) problem for geodesic triangles on a C2 complete surface and on an Aleksandrov space of curvature bounded above by a real number K and solve an “inverse” problem on a C2 complete surface. The solution of the w.F-T problem and the inverse w.F-T problem on a C2 complete surface is based on the differentiation of the length of geodesics with respect to the arc length. 相似文献
9.
Jinbiao Wu 《偏微分方程(英文版)》1999,12(4):313-323
Interface problems for elliptic systems of second order partial differential equations are studied. The main result is that the solution in the neighborhood of the singular point can be divided into two parts one of which is a solution to the homogeneous system with constant coefficients, and the other one possesses higher regularity. 相似文献
10.
A school bus scheduling problem 总被引:1,自引:0,他引:1
This paper introduces a school bus scheduling problem wherein trips for each school are given. A trip consists of a sequence of bus stops and their designated school. Each school has its fixed time window within which trips should be completed. A school bus can serve multiple trips for multiple schools. The school bus scheduling problem seeks to optimize bus schedules to serve all the given trips considering the school time windows. We first model the problem as a vehicle routing problem with time windows (VRPTW) by treating a trip as a virtual stop. Two assignment problem based exact approaches are then proposed for special cases and a heuristic algorithm is proposed for more general cases. Benchmark problems and computational experiments are presented. Computational experiments show the effectiveness of the proposed approaches. 相似文献
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结合生产实际中具体的下料问题,本文建立了该类问题的优化模型,并提出下料方式的遴选三准则,即高利用率优先准则,长度优先准则和时间优先准则.运用本文的算法对一维下料的利用率高达99.6%,机器时间4秒.对二维的利用率为98.9%,机器时间约7秒. 相似文献
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将不平衡运输问题转化成网络最短路问题,利用Floyd算法规则,给出了一种既可以解平衡和不平衡运输问题,又可以解平衡和不平衡分配问题的通用迭代算法。与专门用于解运输问题的闭合回路法和专门用于解分配问题的匈牙利法相比,这种算法不但具有通用的优点,而且更便于在计算机上运行。 相似文献
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Stephen J. Fromm Patrick McDonald 《Proceedings of the American Mathematical Society》1997,125(11):3293-3297
We examine solutions of two related boundary value problems for smooth domains in Euclidean space which arise from variational problems in probability. We show that the existence of solutions to each problem implies that the domain is a sphere.
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Balinski uses his signature method for the proof of the Hirsch-conjecture for dual transportation polyhedra to obtain an efficient
algorithm for the assignment problem. We will show how to extend this method to other primal transportation problems, including
transportation problems with unit demands. We then prove that Balinski's assignment algorithm is equivalent, cycle by cycle,
to that of Hung and Rom. We demonstrate that, under some assumptions for our probability model, a modification of the latter
algorithm has an average complexity of O(n
2logn) and present some computational results confirming this. We also present results that indicate that this modification compares
favorably with Balinski's algorithm and other codes.
Research of both authors supported, in part, by grants of the Alexander von Humboldt-Stiftung.
Supported, in part, by NSF grant DMS-8504050. 相似文献
17.
In this paper, we study a final value problem for first order abstract differential equation with positive self-adjoint unbounded operator coefficient. This problem is ill-posed. Perturbing the final condition we obtain an approximate nonlocal problem depending on a small parameter. We show that the approximate problems are well posed and that their solutions converge if and only if the original problem has a classical solution. We also obtain estimates of the solutions of the approximate problems and a convergence result of these solutions. Finally, we give explicit convergence rates. 相似文献
18.
M.D. Voisei 《Journal of Mathematical Analysis and Applications》2007,335(2):948-961
The identification of the nonlinearity in the equation
19.
Katarina Cechlárová 《Mathematical Methods of Operations Research》1998,47(2):243-254
LetG = (U,V,E) be a bipartite graph with weights of its edgesc
ij
. For the assignment and transportation problem given by such a graph we propose efficient procedures for partitioning the edge setE into three classes:E
o is the set of edgesij withx
ij
= 0 for each optimum solution (0-persistent edges);E
1 is the set of edges withx
ij
> 0 and constant for each optimum (1-persistent edges) andE
w
is the set of edges such that there are two optimum solutions x, x withx
ij
x
ij
1 (weakly persistent edges). 相似文献
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