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2.
The velocity of an incompressible flow in a bounded three‐dimensional domain is represented by its vorticity with the help of an apparently new representation formula. Using this formula we prove a quasi‐Lipschitz estimate for in dependence of the supremum norm of . Our quasi‐Lipschitz bound extends to the case where is represented by any continuous ≠ rot 相似文献
3.
Recently new models of data envelopment analysis (DEA) were introduced that incorporate production trade-offs between inputs and outputs or based on them weight restrictions. In this paper, we develop a computational procedure suitable for the practical application of such models. We show that the standard two-stage optimisation procedure used in DEA to test the full efficiency of units and identify their efficient targets may work incorrectly in the new models. The modified procedure consists of three stages: the first evaluates the radial efficiency of the unit, the second identifies its efficient target, and the third its reference set of efficient peers. Each stage requires solving one linear program for each unit. 相似文献
4.
C. Villani 《Journal of Functional Analysis》2008,255(9):2683-2708
A certain curvature condition, introduced by Ma, Trudinger and Wang in relation with the regularity of optimal transport, is shown to be stable under Gromov-Hausdorff limits, even though the condition implicitly involves fourth order derivatives of the Riemannian metric. Two lines of reasoning are presented with slightly different assumptions, one purely geometric, and another one combining geometry and probability. Then a converse problem is studied: prove some partial regularity for the optimal transport on a perturbation of a Riemannian manifold satisfying a strong form of the Ma-Trudinger-Wang condition. 相似文献
5.
Let be a positive integer. In this paper, we prove that for a graph with at least vertices, if max for any pair of nonadjacent vertices , then contains disjoint cycles. This generalizes the results given by Corrá di and Hajnal (1963), Enomoto (1998), and Wang (1999). 相似文献
6.
N. T. Zung 《Regular and Chaotic Dynamics》2007,12(6):680-688
In this paper we show that, if an integrable Hamiltonian system admits a nondegenerate hyperbolic singularity then it will
satisfy the Kolmogorov condegeneracy condition near that singularity (under a mild additional condition, which is trivial
if the singularity contains a fixed point).
相似文献
7.
Leonid A. Kurdachenko Jose M. Muñoz-Escolano Javier Otal Nicolaj N. Semko 《Geometriae Dedicata》2009,138(1):69-81
Let F be a field and V a vector space over F. If G is a subgroup of GL(V, F), then we define the central dimension of
G (denoted by centdim
F
G) as the F-dimension of the factor-space V/C
V
(G). In this paper, we continue the study of locally nilpotent linear groups satisfying the weak minimal or the weak maximal
condition on their subgroups of infinite central dimension started in Kurdachenko et al. (Publ Mat 52:151–169, 2008).
Supported by Proyecto MTM2007-60994 of Dirección General de Investigación MEC (Spain). 相似文献
8.
Nayandeep Deka Baruah Nipen Saikia 《Journal of Computational and Applied Mathematics》2003,160(1-2):37-51
In 2001, Jinhee Yi found many explicit values of the famous Rogers–Ramanujan continued fraction by using modular equations and transformation formulas for theta-functions. In this paper, we use her method to find some general theorems for the explicit evaluations of Ramanujan's cubic continued fraction. 相似文献
9.
Zhuan Ye 《Transactions of the American Mathematical Society》2004,356(12):4829-4838
We show an analogue of continued fractions in approximation to irrational numbers by rationals for Nevanlinna theory. The analogue is a sequence of points in the complex plane which approaches a given finite set of points and at a given rate in the sense of Nevanlinna theory.
10.
给出带不等式约束的非光滑多目标优化问题正则条件的一个例子.通过该例,指出最近由Burachik和Rizvi利用线性化锥提出的可微多目标优化问题的正则条件不能利用Clarke导数推广到非光滑情形. 相似文献
11.
Determining the number of embeddings of Laman graph frameworks is an open problem which corresponds to understanding the solutions of the resulting systems of equations. In this paper we investigate the bounds which can be obtained from the viewpoint of Bernstein's Theorem. The focus of the paper is to provide methods to study the mixed volume of suitable systems of polynomial equations obtained from the edge length constraints. While in most cases the resulting bounds are weaker than the best known bounds on the number of embeddings, for some classes of graphs the bounds are tight. 相似文献
12.
A mathematical model describing the bubble growth in nucleate boiling is proposed based on non-equilibrium thermodynamics.
Numerical simulation of the bubble growth process is performed. Some new arguments are suggested to explain the phenomenon
which are distinct from the existing articles.
Project supported by the National Natural Science Foundation of China. 相似文献
13.
Shape derivative of the volume integral operator in electromagnetic scattering by homogeneous bodies
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Hamdi Sakly 《Mathematical Methods in the Applied Sciences》2017,40(18):7125-7138
We study the shape derivative of the strongly singular volume integral operator that describes time‐harmonic electromagnetic scattering from homogeneous medium. We show the existence and a representation of the derivative, and we deduce a characterization of the shape derivative of the solution to the diffraction problem as a solution to a volume integral equation of the second kind. 相似文献
14.
对混合位置分布族,当混合比已知时,提出了关于分量参数的假设检验和区间估计方法,所提出的方法基于广义枢轴模型.在一定的条件下,检验的实际水平等于名义水平,且各置信域的实际覆盖率等于名义覆盖率.在更一般的场合,检验是相合的,并且各置信域的实际覆盖率趋于名义覆盖率.模拟显示所给的方法是令人满意的. 相似文献
15.
A general algorithm for building a uniform asymptotic solution of the kinetic equations for spatially inhomogeneous reactive gas mixtures is proposed. It solves the problem of irregular asymptotic solution arising in the ordinary Chapman–Enskog method, providing expressions for chemical reaction rates that agree with the mono-molecular reaction theory. We study a quasi-stationary behavior of the system, characterized by the slowly varying gas-dynamic variables which number is greater than the number of integral invariants of the collision operator. The gas-dynamic equations for reacting and relaxing gas mixtures are derived in general form. It is shown that accurate treatment of non-equilibrium processes gives rise to additional terms caused by the strong influence of small perturbations of quasi-equilibrium distribution functions on the kinetics of high-threshold physical and chemical processes. These terms are describing the influence of inelastic collisions, expansion/compression processes and spatial non-uniformity of gas-dynamic variables. 相似文献
16.
Let y = y(x) be a function defined by a continued fraction. A lower bound for |Λ| = |β
1
y
1 + β
2
y
2 + α| is given, where y
1 = y(x
1), y
2 = y(x
2), x
1 and x
2 are positive integers, α, β
1 and β
2 are algebraic irrational numbers. 相似文献
17.
《Expositiones Mathematicae》2023,41(1):186-201
A series of physically motivated operations appearing in the study of composite materials are interpreted in terms of elementary continued fraction transforms of matrix valued, rational Stieltjes functions. 相似文献
18.
A criterion for the explicit reconstruction of a holomorphic function from its restrictions on lines
We deal with a problem of the explicit reconstruction of any holomorphic function f on a ball of C2 from its restrictions on a union of complex lines. The validity of such a reconstruction essentially depends on the mutual repartition of these lines. This criterion can be analytically described and it is also possible to give geometrical sufficient conditions. The motivation of this problem also comes from possible applications in mathematical economics and medical imaging. 相似文献
19.
This paper is concerned with the statistical modeling of the dependence structure of multivariate financial data using the copula, and the application of copula functions in VaR valuation. After the introduction of the pure copula method and the maximum and minimum mixture copula method, authors present a new algorithm based on the more generalized mixture copula functions and the dependence measure, and apply the method to the portfolio of Shanghai stock composite index and Shenzhen stock component index. Comparing with the results from various methods, one can find that the mixture copula method is better than the pure Gaussian copula method and the maximum and minimum mixture copula method on different VaR level. 相似文献
20.
Moncef Aouadi 《Applicable analysis》2013,92(12):2169-2187
In this article, we investigate the asymptotic behaviour of solutions to the one-dimensional initial-boundary value problem in the linear theory of thermoelastic diffusion mixtures recently developed by Aouadi [M. Aouadi, Qualitative results in the theory of thermoelastic diffusion mixtures, J. Thermal Stresses 33 (2010), pp. 595–615]. Our main result is to establish the necessary and sufficient conditions over the coefficients of the system to get the exponential stability of the corresponding semigroup. 相似文献