Now showing items 1-6 of 6

    • A survey of isochronous centers 

      Chavarriga Soriano, Javier; Sabatini, Marco (Edicions de la Universitat de Lleida, 1999)
    • Centers for the Kukles homogeneous systems with even degree 

      Giné, Jaume; Llibre, Jaume; Valls, Claudia (Shanghai Normal University & Wilmington Scientific Publisher, 2017)
      For the polynomial differential system x˙=−y, y˙=x+Qn(x,y), where Qn(x,y) is a homogeneous polynomial of degree n there are the following two conjectures done in 1999. (1) Is it true that the previous system for n≥2 has a ...
    • Chiellini Hamiltonian Liénard differential systems 

      Giné, Jaume; Llibre, Jaume; Valls, Claudia (Texas State University, 2019)
      We characterize the centers of the Chiellini Hamiltonian Li´enard second-order differential equations x 0 = y, y 0 = −f(x)y − g(x) where g(x) = f(x)(k − α(1 + α) R f(x)dx) with α, k ∈ R. Moreover we study the ...
    • Integrability of a linear center perturbed by a fifth degree homogeneous polynomial 

      Chavarriga Soriano, Javier; Giné, Jaume (Universitat Autònoma de Barcelona. Departament de Matemàtiques, 1997)
      In this work we study the integrability of two-dimensional autonomous system in the plane with linear part of center type and non-linear part given by homogeneous polynomials of fifth degree. We give a simple characterisation ...
    • Integrability of a linear center perturbed by a fourth degree homogeneous polynomial 

      Chavarriga Soriano, Javier; Giné, Jaume (Universitat Autònoma de Barcelona. Departament de Matemàtiques, 1996)
      In this work we study the integrability of a two-dimensional autonomous system in the plane with linear part of center type and non-linear part given by homogeneous polynomials of fourth degree. We give sufficient conditions ...
    • The null divergence factor 

      Chavarriga Soriano, Javier; Giacomini, Héctor; Giné, Jaume (Universitat Autònoma de Barcelona. Departament de Matemàtiques, 1997)
      Let (P, Q) be a C 1 vector field defined in a open subset U ⊂ R2 . We call a null divergence factor a C 1 solution V (x, y) of the equation P ∂V + Q ∂V = ∂P + ∂Q V . In previous works ∂x ∂y ∂x ∂y it has been ...