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91.
《Communications in Nonlinear Science & Numerical Simulation》2014,19(3):758-761
In the commented paper the authors study some aspects of boundedness in the general Lorenz family, , considering that it contains four independent parameters. However, as we show here by means of a linear scaling in time and coordinates, they are dealing with a system homothetically equivalent to the Lorenz system. Consequently, the novel and interesting results they provide for the general Lorenz family can be obtained working directly with the Lorenz equations, that is, dealing only with three independent parameters. 相似文献
92.
Geometric structures of a manifold of positive definite Hermite matrices are considered from the viewpoint of information geometry.A Riemannian metric is defined and dual α-connections are introduced.Then the fact that the manifold is ±l-flat is shown.Moreover,the divergence of two points on the manifold is given through dual potential functions.Furthermore,the optimal approximation of a point onto the submanifold is gotten.Finally,some simulations are given to illustrate our results. 相似文献
93.
94.
In this paper, we study groups of positive operators on Banach lattices. If a certain factorization property holds for the elements of such a group, the group has a homomorphic image in the isometric positive operators which has the same invariant ideals as the original group. If the group is compact in the strong operator topology, it equals a group of isometric positive operators conjugated by a single central lattice automorphism, provided an additional technical assumption is satisfied, for which we have only examples. We obtain a characterization of positive representations of a group with compact image in the strong operator topology, and use this for normalized symmetric Banach sequence spaces to prove an ordered version of the decomposition theorem for unitary representations of compact groups. Applications concerning spaces of continuous functions are also considered. 相似文献
95.
We consider semilinear Neumann equations with an indefinite and unbounded potential. We establish the existence and uniqueness of positive solutions. We show that our setting incorporates as special cases several parametric equations of interest (such as the equidiffusive logistic equation). 相似文献
96.
In this work, we are interested to obtain some result of existence and nonex- istence of positive weak solution for the following p-Laplacian system
{-△piui=λifi(u1,^…,um),inΩ, i=1,...,m, ui=0,
on δΩ,Vi=1,…,m,
where △piz = div(|△z|^pi-2△Z), Pi ≥ 1,λi,1 ≤ i ≤ m are a positive parameter, and Ω is a bounded domain in IR^N with smooth boundary δΩ. The proof of the main results is based to the method of sub-supersolutions. 相似文献
{-△piui=λifi(u1,^…,um),inΩ, i=1,...,m, ui=0,
on δΩ,Vi=1,…,m,
where △piz = div(|△z|^pi-2△Z), Pi ≥ 1,λi,1 ≤ i ≤ m are a positive parameter, and Ω is a bounded domain in IR^N with smooth boundary δΩ. The proof of the main results is based to the method of sub-supersolutions. 相似文献
97.
滕志东 《新疆大学学报(理工版)》2005,22(1):9-16
本文研究一般非自治单种群Kolmgorov时滞生态系统.关于种群的持久性和系统的正周期解的存在性的充分条件被建立,作为这些准则的应用,一系列特殊的单种群增长的时滞系统被研究.关于种群的持久性和系统的正周期解的存在性的一系列具体的判别准则被建立. 相似文献
98.
Xianfeng ZHAO 《数学年刊B辑(英文版)》2016,37(4):533-542
This paper deals with the relationship between the positivity of the Fock Toeplitz operators and their Berezin transforms. The author considers the special case of the bounded radial function φ(z) = a + be~(-α|z|~2)+ ce~(-β|z|~2), where a, b, c are real numbers and α, β are positive numbers. For this type of φ, one can choose these parameters such that the Berezin transform of φ is a nonnegative function on the complex plane, but the corresponding Toeplitz operator Tφ is not positive on the Fock space. 相似文献
99.
保继光 《数学物理学报(A辑)》2002,22(3):348-352
在一般有界区域上,建立了次线性椭圆方程广义Dirichlet问题改进的正解估计和有界强解的存在性定理. 相似文献
100.