Left-Definite Regular Hamiltonian Systems

Linear Hamiltonian systems allow us to generalize, as well as consider, self-adjoint problems of any even order. Such left-definite problems are interesting, not only because of the generalization, but also because of the new intricacies they expose, some of which have made it possible to go beyond fourth order scale problems. We explore the left definite Sobolev settings for such problems, which are in general subspaces determined by boundary conditions. We show that the Hamiltonian operator remains self-adjoint, and inherits the same resolvent and spectral resolution from its original L² space when set in the left-definite Sobolev space.     

左定Sturm-Liouville算子的特征值计算(英文)

研究了定义在有限区间[a,b]上的具有分离型和混合型边界条件的左定正则Sturm-Liouville算子的特征值问题.把具有混合型边界条件的左定正则Sturm-Liouville问题转化成二维的、具有分离型边界条件的右定正则Sturm-Liouville问题,给出了具有混合型边界条件的左定正则Sturm-Liouville算子的特征值的数值计算方法.     

常型Sturm-Liouville问题的左定边值条件

本文刻画了常型Sturm-Liouville问题的左定边值条件．通过Sturm-Liouville微分算式的系数、区间端点以及边值条件给出了其左定性的充要条件．应用自伴边值条件分类,确切地给出了所有可能的左定边值条件．     

Hamiltonian Systems with Positive Topological Entropy and Conjugate Points

In this article, we consider the geodesic flows induced by the natural Hamiltonian systems $H(x,p)=\frac{1}{2}g^{ij}(x) p_{i}p_{j} + V(x) $ defined on a smooth Riemannian manifold$(M = \mathbb{S}^{1} \times N, g)$, where $\mathbb {S}^{1}$ is the one dimensional torus, N is a compact manifold, g is the Riemannian metric on M and V is a potential function satisfying $V \leq 0$. We prove that under suitable conditions, if the fundamental group $\pi_{1}(N)$ has sub-exponential growth rate, then the Riemannian manifold M with the Jacobi metric $(h-V)g$, i.e., $(M, (h-V)g)$, is a manifold with conjugate points for all h with $0 < h <\delta$, where $\delta$ is a small number.     

左定与定型Sturm-Liouville问题间特征值不等式

应用左定和定型Sturm-Liouville问题特征值的Prüfer角刻画,以及其特征值对边界和边值条件的单调依赖关系,本文建立了左定Sturm-Liouville与两个相关的定型Sturm-Liouville问题之间的特征值不等式关系.     

The Hamiltonian Systems of the LCZ Hierarchy by Nonlinearization

In this paper, we first search for the Hamiltonian structure of LCZ hierarchy by use of a trace identity. Then we determine a higher-order constraint condition between the potentials and the eigenfunctions of the LCZ spectral prob lem and under this constraint condition, the Lax pairs of LCZ hierarchy are all nonlinearized into the finite-dimensional integrable Hamiltonian systems in Liouville sense.     

辛映射与Hamilton控制系统

给定等价辛流形 ,即辛同态或形变等价的辛流形 ,研究了建立在这些辛流形上的Hamilton控制系统之间的一些性质的联系 ,诸如 (局部 )能观测性 ,强可接近性 ,(拟 )极小性等 .而且 ,利用Cort啨ｓ介绍的 (弱 )外等价系统的概念 ,给出使得两个Hamilton控制系统是辛同态的一个充分条件     

The Isoenergetic KAM-Type Theorem at Resonant Case for Nearly Integrable Hamiltonian Systems

In this paper, we study the persistence of resonant invariant tori on energy surfaces for nearly integrable Hamiltonian systems under the usual R$\ddot{u}$ssmann nondegenerate condition. By a quasilinear iterative scheme, we prove the following things: (1) The majority of resonant tori on a given energy surface will be persisted under R$\ddot{u}$ssmann nondegenerate condition. (2) The maximal number about the preserved frequency components on a perturbed torus is characterized by the smaller of the maximal rank of the Hessian matrices of the unperturbed system and the nondegeneracy of resonance. (3) If unperturbed systems admit subisoenergetic nondegeneracy on an energy surface, then the majority of the unperturbed resonant tori on the energy surface will be persisted and give rise to a family of perturbed tori with the same energy, whose frequency ratios among respective ''nondegenerate'' components are preserved.     

Special Quasigraded Lie Algebras and Integrable Hamiltonian Systems

We construct a family of special quasigraded Lie algebras of functions of one complex variables with values in finite-dimensional Lie algebra , labeled by the special 2-cocycles F on . The main property of the constructed Lie algebras is that they admit Kostant-Adler-Symes scheme. Using them we obtain new integrable finite-dimensional Hamiltonian systems and new hierarchies of soliton equations.     

Hamiltonian Systems: Stable or Unstable?

This is a review concerning some topics in the field of Hamiltonian dynamics, with emphasis on the problem of Arnold diffusion. Lecture held in the Seminario Matematico e Fisico on January 16, 2006 Received: May 2006     

一类二阶非自治Hamilton系统的周期解

在线性增长和次线性增长条件下,利用临界点理论中的极小作用原理和鞍点定理,研究了二阶非自治Hamilton系统周期解的存在性问题,获得了一些新的可解性条件．     

Brake Subharmonic Solutions of Subquadratic Hamiltonian Systems

The author mainly uses the Galerkin approximation method and the iteration inequalities of the L-Maslov type index theory to study the properties of brake subharmonic solutions for the Hamiltonian systems z(t) = J▽H(t, z(t)), where H(t, z) =1/2(B(t)z, z) +H(t, z),B(t) is a semipositive symmetric continuous matrix andH is unbounded and not uniformly coercive. It is proved that when the positive integers j and k satisfy the certain conditions, there exists a_j T-periodic nonconstant brake solution z_j such that z_j and z_(kj) are distinct.     

KAM-Type Theorem on Resonant Surfaces for Nearly Integrable Hamiltonian Systems

Summary. In this paper, we consider analytic perturbations of an integrable Hamiltonian system in a given resonant surface. It is proved that, for most frequencies on the resonant surface, the resonant torus foliated by nonresonant lower dimensional tori is not destroyed completely and that there are some lower dimensional tori which survive the perturbation if the Hamiltonian satisfies a certain nondegenerate condition. The surviving tori might be elliptic, hyperbolic, or of mixed type. This shows that there are many orbits in the resonant zone which are regular as in the case of integrable systems. This behavior might serve as an obstacle to Arnold diffusion. The persistence of hyperbolic lower dimensional tori has been considered by many authors [5], [6], [15], [16], mainly for multiplicity one resonant case. To deal with the mechanisms of the destruction of the resonant tori of higher multiplicity into nonhyperbolic lower dimensional tori, we have to deal with some small coefficient matrices that are the generalization of small divisors. Received December 18, 1997; revised December 30, 1998; accepted June 21, 1999     

一类非线性哈密顿系统的周期解

结合Maslov指标理论,利用环绕定理证明了一类非线性哈密顿系统的周期解的存在性,而这类哈密顿系统所对应的作用泛函可能不满足Palais-Smale条件.     

Longtime Behaviour of Stochastic Hamiltonian Systems: The Multidimensional Case

Hamiltonian systems perturbed by a white noise force are discussed in several dimensions. By using an appropriate scaling of the stochastic force a convergence theorem for the invariants of the deterministic motion is proved. This corresponds to convergence of the system to a stationary distribution. Especially motion in a central force field is considered; the energy and angular momentum processes are investigated.     

Infinite-Dimensional Hamiltonian and Lagrangian Systems with Constraints

Mathematical Notes -     

Enumerating the Walecki‐Type Hamiltonian Cycle Systems

Let be the complete graph on v vertices. A Hamiltonian cycle system of odd order v (briefly ) is a set of Hamiltonian cycles of whose edges partition the edge set of . By means of a slight modification of the famous of Walecki, we obtain 2ⁿ pairwise distinct and we enumerate them up to isomorphism proving that this is equivalent to count the number of binary bracelets of length n, i.e. the orbits of , the dihedral group of order 2n, acting on binary n‐tuples.     

Some remarks concerning weakly disconjugate linear Hamiltonian systems

We study properties of weakly disconjugate linear Hamiltonian systems. We characterize this concept in terms of a nonoscillation condition. We then show how to approximate a weakly disconjugate system by one with an exponential dichotomy.