Some perturbation results for non-linear problems
We discuss the existence of closed geodesic on a Riemannian manifold and the existence of periodic solution of second order Hamiltonian systems.
We discuss the existence of closed geodesic on a Riemannian manifold and the existence of periodic solution of second order Hamiltonian systems.
We are interested in deformations of Baker domains by a pinching process in curves. In this paper we deform the Fatou function , depending on the curves selected, to any map of the form , p/q a rational number. This process deforms a function with a doubly parabolic Baker domain into a function with an infinite number of doubly parabolic periodic Baker domains if p = 0, otherwise to a function with wandering domains. Finally, we show that certain attracting domains can be deformed by a pinching...
We present some regularity properties of periodic solutions to a class of singular potential problems and we discuss the existence of a regular solution.
Si studia l'andamento delle traiettorie di un sistema dinamico piano rappresentato dalle equazioni (1) del testo, nell'intorno di un punto singolare isolato.
The first part of this paper is concerned with geometrical and cohomological properties of Lie flows on compact manifolds. Relations between these properties and the Euler class of the flow are given.The second part deals with 3-codimensional Lie flows. Using the classification of 3-dimensional Lie algebras we give cohomological obstructions for a compact manifold admits a Lie flow transversely modeled on a given Lie algebra.
We show that the theorem proved in [8] generalises the previous results concerning orientation-preserving iterative roots of homeomorphisms of the circle with a rational rotation number (see [2], [6], [10] and [7]).
Given a Hilbert space with a Borel probability measure , we prove the -dissipativity in of a Kolmogorov operator that is a perturbation, not necessarily of gradient type, of an Ornstein-Uhlenbeck operator.
It is known that a set of positive integers is a Poincaré set (also called intersective set, see I. Ruzsa (1982)) if and only if , where and denotes the Hausdorff dimension (see C. Bishop, Y. Peres (2017), Theorem 2.5.5). In this paper we study the set by replacing with . It is surprising that there are some new phenomena to be worthy of studying. We study them and give several examples to explain our results.