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A Poincaré-Birkhoff theorem for multivalued successor maps with applications to periodic superlinear Hamiltonian systems

Guglielmo Feltrin, Alessandro Fonda, Andrea Sfecci

Abstract

We provide a new version of the Poincaré-Birkhoff theorem for possibly multivalued successor maps associated with planar non-autonomous Hamiltonian systems. As an application, we prove the existence of periodic and subharmonic solutions of the scalar second order equation $\ddot x + λg(t,x) = 0$, for $λ>0$ sufficiently small, with $g(t,x)$ having a superlinear growth at infinity, without requiring the existence of an equilibrium point.

A Poincaré-Birkhoff theorem for multivalued successor maps with applications to periodic superlinear Hamiltonian systems

Abstract

We provide a new version of the Poincaré-Birkhoff theorem for possibly multivalued successor maps associated with planar non-autonomous Hamiltonian systems. As an application, we prove the existence of periodic and subharmonic solutions of the scalar second order equation , for sufficiently small, with having a superlinear growth at infinity, without requiring the existence of an equilibrium point.

Paper Structure

This paper contains 11 sections, 15 theorems, 109 equations, 4 figures.

Key Result

Corollary 1.1

For any integer $N$, there exists $\lambda_N>0$ such that, for every $\lambda \in\mathopen{]}0,\lambda_N\mathclose{]}$, equation ela has at least $N$ periodic solutions.

Figures (4)

  • Figure 1: Qualitative representation of hypotheses \ref{['hp-A-4']} (concerning the area colored in light gray) and \ref{['hp-A-5']} (concerning the area colored in dark gray).
  • Figure 2: Qualitative representation of the statement of Theorem \ref{['successor_thm']}.
  • Figure 3: a) The set $\bighat {\mathcal{C}}_j$ delimiting the interior regions $\bighat{\mathcal{I}}_j$ and the exterior regions $\bighat{\mathcal{E}}_j$. The arrows suggest the direction of the vector field associated with \ref{['HS-lambda']}, see Lemma \ref{['lem-xx']}. b) A sketch of Proposition \ref{['prop-xx']} in the case $m=1$.
  • Figure 4: a) The set $\bigcheck {\mathcal{C}}_j$ delimiting the interior regions $\bigcheck{\mathcal{I}}_j$ and the exterior regions $\bigcheck{\mathcal{E}}_j$. The arrows suggest the direction of the vector field associated with \ref{['HS-lambda']}, see Lemma \ref{['lem-xx2']}. b) A sketch of Proposition \ref{['prop-xx2']} in the case $m=1$.

Theorems & Definitions (33)

  • Corollary 1.1
  • Remark 2.1
  • Remark 2.2
  • Proposition 2.3
  • proof
  • Proposition 2.4
  • Remark 2.5
  • Theorem 3.1
  • Remark 3.2
  • Remark 3.3
  • ...and 23 more