共查询到20条相似文献,搜索用时 765 毫秒
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Yafang KONG 《Frontiers of Mathematics in China》2022,17(6):1001
In this paper, we study the multivariate linear equations with arbitrary positive integral coefficients. Under the Generalized Riemann Hypothesis, we obtained the asymptotic formula for the linear equations with more than five prime variables. This asymptotic formula is composed of three parts, that is, the first main term, the explicit second main term and the error term. Among them, the first main term is similar with the former one, the explicit second main term is relative to the non-trivial zeros of Dirichlet L-functions, and our error term improves the former one. 相似文献
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Kyung-Tae Kang 《Linear and Multilinear Algebra》2013,61(2):241-247
We obtain some characterizations of linear operators that preserve the term rank of Boolean matrices. That is, a linear operator over Boolean matrices preserves the term rank if and only if it preserves the term ranks 1 and k(≠1) if and only if it preserves the term ranks 2 and l(≠2). Other characterizations of term rank preservers are given. 相似文献
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股票价格在漂移项和扩散项具有时滞,且股票在期权有效期内支付连续红利时,利用鞅表示定理和Girsanov定理得到了期权价格的闭式解.研究表明,股票价格在漂移项和扩散项具有时滞时,股票支付红利时对期权价格有一个调整. 相似文献
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在变指数背景下,我们考虑了一类具零阶项的抛物方程解的存在性结果. 存在性的证明在本质上依赖于选取合适的检验函数,这些检验函数要同时兼顾方程右端源项的可积性和零阶项. 利用先验估计和极限分析,借助于Young测度方法确立了非线性项的弱收敛元. 相似文献
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Yunyun Yang Sichun Ruan Xuxu Qin Dongcai Tian 《Mathematical Methods in the Applied Sciences》2019,42(4):1059-1072
In this paper, we propose a new fast level set model of multi‐atlas labels fusion for 3D magnetic resonance imaging (MRI) tissues segmentation. The proposed model is aimed at segmenting regions of interest in MR images, especially the tissues such as the amygdala, the caudate, the hippocampus, the pallidum, the putamen, and the thalamus. We first define a new energy functional by taking full advantage of an image data term, a length term, and a label fusion term. Different from using the region‐scalable fitting image data term and length term directly, we define a new image data term and a new length term, which is also incorporated with an edge detect function. By introducing a spatially weight function into the label fusion term, segmentation sensitivity to warped images can be largely improved. Furthermore, the special structure of the new energy functional ensures the application of the split Bregman method, which is a significant highlight and can improve segmentation efficiency of the proposed model. Because of these promotions, several good characters, such as accuracy, efficiency, and robustness have been exhibited in experimental results. Quantitative and qualitative comparisons with other methods have demonstrated the superior advantages of the proposed model. 相似文献
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P. T. Liu 《Journal of Optimization Theory and Applications》1979,27(4):539-547
In this paper, two linear-quadratic systems are shown to be asymptotically decoupled. We obtain the steady-state term and the first-order transient term of optimal controls. We also obtain an estimate of the rate at which the first-order transient term diminishes and approaches zero. 相似文献
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B. Yu. Konev 《Journal of Mathematical Sciences》2003,118(2):4982-4993
We prove an upper bound on the height of terms occurring in the most general unifier for the case where the set of term variables splits to two subsets. A term variable belongs to the first subset if the depths of all its occurrences coincide; we call such a variable a term variable of the cut type. Otherwise, a term variable belongs to the second subset. We bound from above the height of terms occurring in the most general unifier by the number of term variables not of the cut type and the size of the given unification problem. This bound implies an upper bound on the size of terms occurring in proofs in a sequent-style calculus with bound-depth-restricted cuts. Bibliography: 18 titles. 相似文献
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利率风险溢酬是长期利率的组成部分,解读它所包含的信息、寻找它的来源有着重要的经济意义。本文先使用利率仿射模型,计算出先验的中国国债利率期限溢酬,然后构建VECM模型,运用脉冲响应、方差分析等技术,分析国债利率的风险溢酬和主要宏观经济变量的动态关系,发现宏观变量对溢酬的影响在当期和滞后几期有明显差异,CPI和GDP是影响最大的两个因素,但信贷供应量和M1的作用也较大。我们同时也发现银行间市场投资者比交易所市场投资者更易受到宏观经济的影响。 相似文献
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This paper studies the optimal trade credit term decision in an extended economic ordering quantity (EOQ) framework that incorporates a default risk component. A principal-agent bilevel programming model with costs minimization objectives is set up to derive the incentive-compatible credit term. The supplier determines the credit term as the leader in the first level programming, by balancing her/his financing capacity with the retailer’s default risk, order behavior and cost shifting. At the second level, the retailer makes decisions on ordering and payment time by reacting on the term offered by the supplier. A first order condition solution procedure is derived for the bilevel programming when credit term is confined within the practically feasible interval. Two key results are obtained – the condition to derive incentive-compatible credit term, and an equation system to derive threshold default risk criterion filtering retailers suitable for credit granting. Numerical experiments show that the capital cost of the supplier is the most important factor determining the credit term. Default risk acts like a filtering criterion for selecting retailers suitable for credit granting. Empirical evidence supporting our theoretical considerations is obtained by estimating three panel econometric models, using a dataset from China’s listed companies. 相似文献
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In this paper, we examine the method of characteristic-mixed finite element for the approximation of convex optimal control problem governed by time-dependent convection-diffusion equations with control constraints. For the discretization of the state equation, the characteristic finite element is used for the approximation of the material derivative term (i.e., the time derivative term plus the convection term), and the lowest-order Raviart-Thomas mixed element is applied for the approximation of the diffusion term. We derive some a priori error estimates for both the state and control approximations. 相似文献
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具两个时滞项的微分方程的稳定性 总被引:3,自引:0,他引:3
本文考虑了一类具两个时滞项的微分方程的稳定性,其中一个时滞项的系数非负,另一个时滞项的系数非正.当非负系数恒为零时,本文所得结论改进了Yorke等提出的3/2稳定性定理的相应结论,当非负系数项的时滞为零,本文不同于已有文献用Liapunov函数或泛函法将时滞项作为干扰处理,而是反过来利用时滞项让方程稳定. 相似文献
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We study a time relaxation regularization of flow problems proposed and tested extensively by Stolz and Adams. The aim of the relaxation term is to drive the unresolved fluctuations in a computational simulation to zero exponentially fast by an appropriate and often problem dependent choice of its coefficient; this relaxation term is thus intermediate between a tunable numerical stabilization and a continuum modeling term. Our aim herein is to understand how this term, by itself, acts to truncate solution scales and to use this understanding to give insight into parameter selection. 相似文献
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Alain Haraux 《manuscripta mathematica》1985,53(1-2):145-166
Under some regularity conditions, a non-resonance property is established for a semi-linear forced wave equation with a strong local damping term and Dirichlet boundary conditions in a bounded open domain. In dimension less than or equal to six, the damping term can grow at infinity like an arbitrarily large power of the velocity. If a viscosity term is added, in dimension less or equal to four a stronger result is obtained, and this property allows to construct almost periodic solutions for an arbitrary forcing term in a suitable regularity class. 相似文献
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In this paper, we focus on the calibration of affine stochastic mortality models using term assurance premiums. We view term assurance contracts as a “swap” in which policyholders exchange cash flows (premiums vs. benefits) with an insurer analogous to a generic interest rate swap or credit default swap. Using a simple bootstrapping procedure, we derive the term structure of mortality rates from a stream of contract quotes with different maturities. This term structure is used to calibrate the parameters of affine stochastic mortality models where the survival probability is expressed in closed form. The Vasicek, Cox-Ingersoll-Ross, and jump-extended Vasicek models are considered for fitting the survival probabilities term structure. An evaluation of the performance of these models is provided with respect to premiums of three Italian insurance companies. 相似文献
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We show that the inertia of a quadratic matrix polynomial is determined in terms of the inertia of its coefficient matrices if the leading coefficient is Hermitian and nonsingular, the constant term is Hermitian, and the real part of the coefficient matrix of the first degree term is definite. In particular, we prove that the number of zero eigenvalues of such a matrix polynomial is the same as the number of zero eigenvalues of its constant term. We also give some new results for the case where the real part of the coefficient matrix of the first degree term is semidefinite. 相似文献