Ara es mostren els items 48-55 de 55

    • Rational parameterizations approach for solving equations in some dynamical systems problems 

      Lázaro Ochoa, José Tomás; Gasull Embid, Armengol; Torregrosa Arús, Joan (2019-08)
      Article
      Accés obert
      We show how the use of rational parameterizations facilitates the study of the number of solutions of many systems of equations involving polynomials and square roots of polynomials. We illustrate the effectiveness of this ...
    • Rational periodic sequences for the Lyness recurrence 

      Gasull Embid, Armengol; Mañosa Fernández, Víctor; Xarles Ribas, Xavier (2010-04-30)
      Altres
      Accés obert
      Consider the celebrated Lyness recurrence $x_{n+2}=(a+x_{n+1})/x_{n}$ with $a\in\Q$. First we prove that there exist initial conditions and values of $a$ for which it generates periodic sequences of rational numbers with ...
    • Stability index of linear random dynamical system 

      Cima Mollet, Anna; Gasull Embid, Armengol; Mañosa Fernández, Víctor (2019-04-11)
      Report de recerca
      Accés obert
      Given a homogeneous linear discrete or continuous dynamical system, its stability index is given by the dimension of the stable manifold of the zero solution. In particular, for the n dimensional case, the zero solution ...
    • Stability index of linear random dynamical systems 

      Cima Mollet, Anna; Gasull Embid, Armengol; Mañosa Fernández, Víctor (2021)
      Article
      Accés obert
      Given a homogeneous linear discrete or continuous dynamical system, its stability index is given by the dimension of the stable manifold of the zero solution. In particular, for the n dimensional case, the zero solution ...
    • The period function for Hamiltonian systems with homogeneous nonlinearities 

      Gasull Embid, Armengol; Guillamon Grabolosa, Antoni; Mañosa Fernández, Víctor; Mañosas Capellades, Francesc (1996)
      Article
      Accés obert
      The paper deals with Hamiltonian systems with homogeneous nonlinearities. We prove that such systems have no isochronous centers, that the period annulus of any of its centres is either bounded or the whole plane and that ...
    • The period function for second-order quadratic ODEs is monotone 

      Gasull Embid, Armengol; Guillamon Grabolosa, Antoni; Villadelprat Yagüe, Jordi (2003)
      Article
      Accés obert
      Very little is known about the period function for large families of centers. In one of the pioneering works on this problem, Chicone [?] conjectured that all the centers encountered in the family of second-order differential ...
    • Upper bounds for the number of zeroes for some Abelian Integrals 

      Lázaro Ochoa, José Tomás; Gasull Embid, Armengol; Torregrosa, Joan (2012-01-12)
      Report de recerca
      Accés obert
      Abstract. Consider the vector field x0 = -yG(x, y), y0 = xG(x, y), where the set of critical points {G(x, y) = 0} is formed by K straight lines, not passing through the origin and parallel to one or two orthogonal ...
    • Upper bounds for the number of zeroes for some Abelian integrals 

      Gasull Embid, Armengol; Lázaro Ochoa, José Tomás; Torregrosa, Joan (2012-09)
      Article
      Accés restringit per política de l'editorial
      Consider the vector field x′=−yG(x,y),y′=xG(x,y), where the set of critical points {G(x,y)=0} is formed by K straight lines, not passing through the origin and parallel to one or two orthogonal directions. We perturb it ...