Ara es mostren els items 1-20 de 20

  • Abundance of attracting, repelling and elliptic periodic orbits in two-dimensional reversible maps 

    Delshams Valdés, Amadeu; Gonchenko, S.V.; Lázaro Ochoa, José Tomás; Stenkin, Oleg (2013-01-01)
    Article
    Accés obert
    We study dynamics and bifurcations of two-dimensional reversible maps having non-transversal heteroclinic cycles containing symmetric saddle fixed points. We consider one-parameter families of reversible maps unfolding ...
  • Abundance of attracting, repelling and elliptic periodic orbits in two-dimensional reversible maps 

    Delshams Valdés, Amadeu; Lázaro Ochoa, José Tomás; Gonchenko, S.V.; Sten'kin, Oleg (2012-01-12)
    Report de recerca
    Accés obert
    Abstract. We study dynamics and bifurcations of two-dimensional reversible maps having non-transversal heteroclinic cycles containing symmetric saddle periodic points. We consider one-parameter families of reversible ...
  • A pseudo-normal form for planar vector fields 

    Delshams Valdés, Amadeu; Guillamon Grabolosa, Antoni; Lázaro Ochoa, José Tomás (2001)
    Article
    Accés obert
  • Breathers in a model of a polymer with secondary structure 

    Kastner, Michael; Lázaro Ochoa, José Tomás (2002)
    Article
    Accés obert
  • Càlcul numèric. Manual de pràctiques 

    Lázaro Ochoa, José Tomás; Ollé Torner, Mercè; Pacha Andújar, Juan Ramón (2014-07)
    Report de recerca
    Accés obert
  • Differential galois theory and non-integrability of planar polynomial vector fields 

    Lázaro Ochoa, José Tomás; Pantazi, Chara; Acosta Humanez, Primitivo; Morales Ruiz, Juan José (2018-02-26)
    Article
    Accés restringit per política de l'editorial
    We study a necessary condition for the integrability of the polynomials vector fields in the plane by means of the differential Galois Theory. More concretely, by means of the variational equations around a particular ...
  • Dynamics and bifurcations in a simple quasispecies model of tumorigenesis 

    Castillo, Vanessa; Lázaro Ochoa, José Tomás; Sardañés, Josep (2015-05-18)
    Article
    Accés obert
    Cancer is a complex disease and thus is complicated to model. However, simple models that describe the main processes involved in tumoral dynamics, e.g., competition and mutation, can give us clues about cancer behavior, ...
  • Effective stability in reversible systems 

    Delshams Valdés, Amadeu; Lázaro Ochoa, José Tomás (1997)
    Article
    Accés obert
    In this paper we present a procedure to put in normal form a nearly-integrable reversible system, not necessarily a Hamiltonian system. Furthermore, non-resonant stability estimates are obtained. As an application we discuss ...
  • Full analysis of small hypercycles with shortcircuits in prebiotic evolution 

    Lázaro Ochoa, José Tomás; Guillamon Grabolosa, Antoni; Fontich, Ernest; Sardañés, Josep (2017-01-05)
    Article
    Accés restringit per política de l'editorial
    It is known that hypercycles are sensitive to the so-called parasites and short-circuits. While the impact of parasites has been widely investigated for well-mixed and spatial hypercycles, the effect of short-circuits in ...
  • Mixed dynamics in reversible maps with gure-8 homoclinic connections 

    Delshams Valdés, Amadeu; Gonchenko, Sergey; Lázaro Ochoa, José Tomás (2014)
    Text en actes de congrés
    Accés obert
    We study dynamics and bifurcations of two-dimensional reversible maps having non-transversal heteroclinic cycles containing symmetric saddle periodic points. We consider one-parameter families of rev ersible maps unfolding ...
  • Mixed dynamics of two-dimensional reversible maps with a symmetric couple of quadratic homoclinic tangencies 

    Lázaro Ochoa, José Tomás; Delshams Valdés, Amadeu; Gonchenko, Marina; Gonchenko, Sergey (American Institute of Mathematical Sciences, 2018-09)
    Article
    Accés restringit per política de l'editorial
    We study dynamics and bifurcations of 2-dimensional reversible maps having a symmetric saddle fixed point with an asymmetric pair of nontransversal homoclinic orbits (a symmetric nontransversal homoclinic figure-8). We ...
  • On Normal Forms and Splitting of Separatrices in Reversible Systems 

    Lázaro Ochoa, José Tomás (Universitat Politècnica de Catalunya, 2003-10-23)
    Tesi
    Accés obert
    És difícil dibuixar una frontera, dins la Teoria de Sistemas Dinàmics, entre lleis de conservació i simetries doncs, sovint, les seves característiques es confonen. Un clar exemple d'aquest fenómen el constitueixen els ...
  • On the Chebyshev property for a new family of functions 

    Lázaro Ochoa, José Tomás; Gasull Embid, Armengol; Torregrosa, Joan (2012-03)
    Article
    Accés obert
  • On the integrability of polynomial fields in the plane by means of Picard-Vessiot theory 

    Lázaro Ochoa, José Tomás; Morales Ruíz, Juan José; Acosta Humánez, Primitivo Belén; Pantazi, Chara (2012-01-12)
    Report de recerca
    Accés obert
    We study the integrability of polynomial vector fields using Galois theory of linear differential equations when the associated foliations is reduced to a Riccati type foliation. In particular we obtain integrability results ...
  • Pseudo-normal form near saddle-center or saddle-focus equilibria 

    Delshams Valdés, Amadeu; Lázaro Ochoa, José Tomás (2003)
    Article
    Accés obert
    In this paper we introduce the pseudo-normal form, which generalizes the notion of normal form around an equilibrium. Its convergence is proved for a general analytic system in a neighborhood of a saddle-center or a ...
  • Pseudo-normal forms and their applications 

    Delshams Valdés, Amadeu; Lázaro Ochoa, José Tomás (2001)
    Article
    Accés obert
  • Tesi doctoral: "On normal forms and splitting of separatrices in reversible systems" 

    Lázaro Ochoa, José Tomás (2003)
    Working paper
    Accés obert
  • 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 ...
  • 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 ...
  • Viral replication modes in single-peak fitness landscapes: A dynamical systems analysis 

    Forners, Joan; Lázaro Ochoa, José Tomás; Alarcón, Tomás; F. Elena, Santiago; Sardanyes, Josep (2019-01-07)
    Article
    Accés restringit per política de l'editorial
    Positiv e-sense, single-stranded RN A viruses are im portant pathogens infecting almost all types of organ- isms. Experimental evidence from distributions of mutations and from viral RN A ampli¿cation suggest that these ...