Periodic solutions for Hamiltonian systems under strong constraining forces

We consider periodic solutions of Hamiltonian systems in Euclidean spaces whose motion is constrained to a submanifold M. We prove that under some nondegeneracy assumptions, periodic solutions persist when the constraint is replaced by a strong restoring potential.     

Hyperbolic-like solutions for singular Hamiltonian systems

We study the existence of unbounded solutions of singular Hamiltonian systems: where is a potential with a singularity. For a class of singular potentials with a strong force , we show the existence of at least one hyperbolic-like solutions. More precisely, for given and , we find a solution q(t) of (*) satisfying Received October 1998     

Non-limit-circle criteria for singular Hamiltonian differential systems

Non-limit-circle criteria for singular Hamiltonian differential expressions with complex coefficients are obtained. The main results are extensions of the previous limit-point criterion due to H. Weyl for second-order differential equations.     

Non-collision periodic solutions for singular Hamiltonian systems

We study the existence of classical (non-collision) T-periodic solutions of the Hamiltonian system where and is a T-periodic function in t which has a singularity at like Under suitable conditions on H, we prove that if then (HS) possesses at least one non-collision solution and if then the generalized solution of (HS) obtained in [5] has at most one time of collision in its period.     

A shadowing lemma for quasi-hyperbolic strings of flows

In this paper we prove a shadowing lemma for pseudo orbits made by quasi-hyperbolic strings. We allow singularities in question and hence, in particular, the quasi-hyperbolic strings are formulated by the rescaled linear Poincaré flow instead of the usual linear Poincaré flow. We also introduce the sectional Poincaré map and rescaled sectional Poincaré map for Lipschitz vector fields on Banach spaces in the article.     

The fixed energy problem for a class of nonconvex singular Hamiltonian systems

We consider a noncompact hypersurface H in R2N which is the energy level of a singular Hamiltonian of “strong force” type. Under global geometric assumptions on H, we prove that it carries a closed characteristic, as a consequence of a result by Hofer and Viterbo on the Weinstein conjecture in cotangent bundles of compact manifolds. Our theorem contains, as particular cases, earlier results on the fixed energy problem for singular Lagrangian systems of strong force type.     

Self-adjoint extensions for linear Hamiltonian systems with two singular endpoints

This paper is concerned with self-adjoint extensions for a linear Hamiltonian system with two singular endpoints. The domain of the closure of the corresponding minimal Hamiltonian operator H₀ is described by properties of its elements at the endpoints of the discussed interval, decompositions of the domains of the corresponding left and right maximal Hamiltonian operators are provided, and expressions of the defect indices of H₀ in terms of those of the left and right minimal operators are given. Based on them, characterizations of all the self-adjoint extensions for a Hamiltonian system are obtained in terms of square integrable solutions. As a consequence, the characterizations of all the self-adjoint extensions are given for systems in several special cases.     

New periodic solutions for a class of singular Hamiltonian systems

In this paper, we apply a variant of the famous Mountain Pass Lemmas of Ambrosetti-Rabinowitz and Ambrosetti-Coti Zelati with (PSC)c type condition of Palais-Smale-Cerami to study the existence of new periodic solutions with a prescribed energy for symmetrical singular second order Hamiltonian conservative systems with weak force type potentials.     

Decoupling of bidiagonal systems involving singular blocks

For one-step difference equations, where the matrix coefficientsmay be singular, a stability analysis based on using fundamentalsolutions and their inverses does not apply. This paper showshow well-boundedness of the Green's function leads to a kindof dichotomy of the fundamental solution, including certain‘parasitic solutions’ (which arise because of thesingularity of the fundamental solutions). This then is usedto show how one can find a stable decoupling and thus a numericalalgorithm for solving a discrete boundary-value problem. Severalexamples sustain the analysis.     

Equivariant normal form for nondegenerate singular orbits of integrable Hamiltonian systems

We consider an integrable Hamiltonian system with n degrees of freedom whose first integrals are invariant under the symplectic action of a compact Lie group G. We prove that the singular Lagrangian foliation associated to this Hamiltonian system is symplectically equivalent, in a G-equivariant way, to the linearized foliation in a neighborhood of a compact singular nondegenerate orbit. We also show that the nondegeneracy condition is not equivalent to the nonresonance condition for smooth systems.     

Limit-point criteria for semi-degenerate singular Hamiltonian differential systems with perturbation terms

Some limit-point criteria are obtained for higher-dimensional semi-degenerate singular Hamiltonian differential systems with perturbation potential terms by using M(λ)-theory. Results in this paper cover many previous results of Hartman, Levinson, Titchmarsh and Read.     

Oscillation theorems for self-adjoint matrix Hamiltonian systems involving general means

By use of monotone functionals and positive linear functionals, a generalized Riccati transformation and the general means technique, some new oscillation criteria for the following self-adjoint Hamiltonian matrix system

(E)     

A remark on periodic solutions of singular Hamiltonian systems

In this note we study the existence of non-collision periodic solutions for singular Hamiltonian systems with weak force. In particular for potential where D is a compact C³-surface in we prove the existence of a non-collision periodic solution.     

Boundedness of solutions for singular Hamiltonian differential systems with applications to deficiency indices

The paper gives boundedness estimation of solutions for singular Hamiltonian differential systems. As corollaries, limit-circle criteria are given and improve some previous results.     

Strong limit point criteria for a class of singular discrete linear Hamiltonian systems

This paper is concerned with the limit point case for a class of singular discrete linear Hamiltonian systems. The limit point case is divided into the strong and the weak limit point cases. Several sufficient conditions for the strong limit point case are established. In consequence, two criteria of the strong limit point case for second-order formally self-adjoint vector difference equations are obtained.     

On strong ergodicity and chaoticity of systems with the asymptotic average shadowing property

Let X be a compact metric space and f: X → X be a continuous map. In this paper, we investigate the relationships between the asymptotic average shadowing property (Abbrev. AASP) and other notions known from topological dynamics. We prove that if f has the AASP and the minimal points of f are dense in X, then for any n ? 1, f × f × ? × f(n times) is totally strongly ergodic. As a corollary, it is shown that if f is surjective and equicontinuous, then f does not have the AASP. Moreover we prove that if f is point distal, then f does not have the AASP. For f: [0, 1] → [0, 1] being surjective continuous, it is obtained that if f has two periodic points and the AASP, then f is Li-Yorke chaotic.     

First-order strong variation algorithm for optimal control problems involving parabolic systems

This paper considers the optimal control of a system governed by a parabolic partial differential equation with first boundary conditions. For this system, a condition of extremality is defined, which is proven to be a necessary condition for optimality. For non-extremal controls, a method of constructing a new control that has an improved criterion value is discussed. It is shown that if a sequence of controls, each constructed from the previous control in the manner discussed, converges, then the limit is extremal.     

First-order strong variation algorithm for optimal control problems involving hyperbolic systems

This paper considers an optimal control problem involving linear, hyperbolic partial differential equations. A first-order strong variational technique is used to obtain an algorithm for solving the optimal control problem iteratively. It is shown that the accumulation points of the sequence of controls generated by the algorithm (if they exist) satisfy a necessary condition for optimality.