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1.
首先简要介绍自1977年左右开始的寻找连续时间马尔可夫跳过程实用的唯一性充分条件的故事.对于一般状态空间的一般性结果是1985年得到的.为展示这些充分条件的精确性,于1991年找到非唯一性的对偶判别准则.本文主要限于离散空间(此时的跳过程也称为Q过程或马尔可夫链).在这种情况下,我们将在文末证明上述充分条件也是必要的.我们还将举例说明不论对于唯一性或非唯一性,我们的充分条件不仅强有力,而且精确.  相似文献   

2.
The necessary and sufficient conditions for the small norm perturbation of a Drazin invertible operator to be still Drazin invertible and the sufficient conditions for the finite rank perturbation of a Drazin invertible operator to be still Drazin invertible are established.  相似文献   

3.
1IntroductionConsidertheneutraldifferentialequationswherepiERfori=l,2,...,m;o相似文献   

4.
获得了著名的AOR方法收敛的实用条件和H矩阵的实用判别条件。所得AOR方法的收敛条件便于实际计算应用,适用范围不要求方程组系数矩阵对角占优,适用于数学物理问题中广泛的矩阵类。给出的数值例子表明了所得结果的实用性。  相似文献   

5.
We consider a class of mathematical programs governed by parameterized quasi-variational inequalities(QVI).The necessary optimality conditions for the optimization problem with QVI constraints are reformulated as a system of nonsmooth equations under the linear independence constraint qualification and the strict slackness condition.A set of second order sufficient conditions for the mathematical program with parameterized QVI constraints are proposed,which are demonstrated to be sufficient for the second o...  相似文献   

6.
The problem of the optimal control of pulse-frequency-modulated (PFM) systems is investigated in this paper. Necessary and sufficient conditions for the linear-quadratic loss PFM case are developed. The basic problem with such conditions involves the computational implementation of the derived results. Here, sufficient conditions for the discrete-time case (DPFM) are obtained to provide ease in computation. It is shown that the conditions, which are developed under total variation constraints, can be utilized to define a simple scheme for solution of the resulting two-point boundary-value problem.  相似文献   

7.
In this paper, we analyze the relation between some classes of matrices with variants of the diagonal dominance property. We establish a sufficient condition for a generalized doubly diagonally dominant matrix to be invertible. Sufficient conditions for a matrix to be strictly generalized diagonally dominant are also presented. We provide a sufficient condition for the invertibility of a cyclically diagonally dominant matrix. These sufficient conditions do not assume the irreducibility of the matrix.  相似文献   

8.
杨文生 《数学杂志》2017,37(3):627-636
本文研究了一类具有修正Leslie-Gower功能性反应的捕食者-食饵模型.利用比较原理以及一些引理的方法,获得了保证食饵绝灭的充分条件以及保证捕食者和食饵永久持续生存的充分必要条件,所得结论完善和补充了前人的结果.  相似文献   

9.
Various first-order and second-order sufficient conditions of optimality for calculus of variations problems with delayed argument are formulated. The cost functionals are not required to be convex. A second-order sufficient condition is shown to be related to the existence of solutions of a Riccati-type matrix differential inequality.  相似文献   

10.
Analogues of ring theory results concerning the Jacobson radical of a regular ring are obtained for near-rings with a two-sided zero. The quasiradical and the radical-subgroup of a regular near-ring are shown to be {0}. Some sufficient conditions are obtained for the radical and the primitiveradical of a regular near-ring to be {0}. Necessary and sufficient conditions are determined for a near-ringR which satisfies d. c. c. onR-subgroups ofR to be regular.  相似文献   

11.
We derive spectral necessary and sufficient conditions for stationary symmetric stable processes to be metrically transitive and mixing. We then consider some important classes of stationary stable processes: Sub-Gaussian stationary processes and stationary stable processes with a harmonic spectral representation are never metrically transitive, the latter in sharp contrast with the Gaussian case. Stable processes with a harmonic spectral representation satisfy a strong law of large numbers even though they are not generally stationary. For doubly stationary stable processes, sufficient conditions are derived for metric transitivity and mixing, and necessary and sufficient conditions for a strong law of large numbers.  相似文献   

12.
We show new results on when a pseudo-slant submanifold is a LCS-manifold. Necessary and sufficient conditions for a submanifold to be pseudo-slant are given. We obtain necessary and sufficient conditions for the integrability of distributions which are involved in the definition of the pseudo-slant submanifold. We characterize the pseudoslant product and give necessary and sufficient conditions for a pseudo-slant submanifold to be the pseudo-slant product. Also we give an example of a slant submanifold in an LCS-manifold to illustrate the subject.  相似文献   

13.
This paper concerns the sufficient conditions of optimality for initial value problem with higher order differential inclusions (HODIs) and free endpoint constraints. Formulation of the transversality conditions plays a substantial role in the next investigations without which hardly any necessary or sufficient conditions would be obtained. In terms of Euler–Lagrange and Hamiltonian forms the sufficient conditions of optimality both for convex and “non-convex” HODIs are based on the apparatus of locally adjoint mappings. Moreover, by applying the main result to a Bolza problem described by a polynomial differential operator with constant coefficients in terms of the adjoint differential operator the sufficient condition of optimality is obtained.  相似文献   

14.
王德胜  张玉芬 《数学研究》1998,31(2):216-220
给出了两个幺半群的半直积及圈积为右(左)逆半群的充分必要条件,从而推广了[2]中两个幺半群的半幺直积和圈积为逆半群的充分必要条件.  相似文献   

15.
We formulate discrete-time analogues of integrodifferential equations modelling bidirectional neural networks studied by Gopalsamy and He. The discrete-time analogues are considered to be numerical discretizations of the continuous-time networks and we study their dynamical characteristics. It is shown that the discrete-time analogues preserve the equilibria of the continuous-time networks. By constructing a Lyapunov-type sequence, we obtain easily verifiable sufficient conditions under which every solution of the discrete-time analogue converges exponentially to the unique equilibrium. The sufficient conditions are identical to those obtained by Gopalsamy and He for the uniqueness and global asymptotic stability of the equilibrium of the continuous-time network. By constructing discrete-time versions of Halanay-type inequalities, we obtain another set of easily verifiable sufficient conditions for the global exponential stability of the unique equilibrium of the discrete-time analogue. The latter sufficient conditions have not been obtained in the literature of continuous-time bidirectional neural networks. Several computer simulations are provided to illustrate the advantages of our discrete-time analogue in numerically simulating the continuous-time network with distributed delays over finite intervals.  相似文献   

16.
New necessary and sufficient conditions are presented for the observability of systems described by nonlinear ordinary differential equations with nonlinear observations. The conditions are based on extension of the necessary and sufficient conditions for observability of time-varying linear systems to the linearized trajectory of the nonlinear system. The result is that the local observability of any initial condition can be readily determined, and the observability of the entire initial domain can be computed. The observability of constant parameters appearing in the differential equations is also considered. Examples are presented to illustrate the theory.This research was supported by the National Science Foundation, Grant No. NSF GK-10136.  相似文献   

17.
Summary Necessary and sufficient conditions are given, for a process to be the excursion process of some strong Markov process. These are modifications of necessary conditions of Itô, which are here shown by example not to be sufficient.  相似文献   

18.
Nonimprovable, in general, estimates of the number of necessary and sufficient conditions for two Hermitian operators to be unitarily equaivalent in a unitary space are obtained when the multiplicities of eigenvalues of operators can be more than 1. The explicit form of these conditions is given. In the Appendix the concept of conditionally functionally independent functions is given and the corresponding necessary and sufficient conditions are presented.  相似文献   

19.
研究了下列二阶中立型差分方程Δ2[x(n)-px(n-τ)]+q(n)x(g(n))=0,n n0正解渐近趋向于零的充分条件.  相似文献   

20.
We present necessary and sufficient conditions for a critical point of certain two-dimensional cubic differential systems to be a centre. Extensive use of the computer algebra system REDUCE is involved. The search for necessary and sufficient conditions for a centre has long been of considerable interest in the theory of nonlinear differential equations. It has proved to be a difficult problem, and full conditions are known for very few classes of systems. Such conditions are also required in the investigation of Hilbert's sixteenth problem concerning the number of limit cycles of polynomial systems.  相似文献   

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