Electronic Journal of Differential Equations,
Vol. 2020 (2020), No. 57, pp. 1-14.

Title: Linear type global centers of cubic Hamiltonian systems symmetric with respect
       to the x-axis
       
Authors: Luis Barreira (Univ. de Lisboa, Portugal)
         Jaume Llibre (Univ.Autonoma de Barcelona, Catalonia, Spain)
         Claudia Valls (Univ. de Lisboa, Portugal)

Abstract:
 A polynomial differential system of degree 2 has no global centers
 (that is, centers defined in all the plane except the fixed point).
 In this paper we characterize the global centers of cubic Hamiltonian
 systems symmetric with respect to the x-axis, and such that the
 center has purely imaginary eigenvalues.
 
Submitted January 10, 2019. Published June 08, 2020.
Math Subject Classifications: 34C05, 34C07, 34C08.
Key Words: Center; global center; Hamiltonian system;
           symmetry with respect to the x-axis; 
           cubic polynomial differential system.