Ara es mostren els items 14-30 de 30

    • 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 obert
      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 dynamics and invariant sets in predator-prey maps 

      Lázaro Ochoa, José Tomás; Alsedà, Lluís; Sardañés, Josep; Vidiella, Blai (2019-11-27)
      Capítol de llibre
      Accés obert
      A multitude of physical, chemical, or biological systems evolving in discrete time can be modelled and studied using difference equations (or iterative maps). Here we discuss local and global dynamics for a predator-prey ...
    • 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 ...
    • On the integrability of polynomial vector fields in the plane by means of Picard-Vessiot theory 

      Acosta-Humànez, Primitivo; Lázaro Ochoa, José Tomás; Morales Ruiz, Juan José; Pantazi, Chara (American Institute of Mathematical Sciences, 2015-05-01)
      Article
      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
    • 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 ...
    • Semiclassical quantification of some two degree of freedom potentials: A differential Galois approach 

      Acosta Humánez, Primitivo Belen; Lázaro Ochoa, José Tomás; Pantazi, Chara; Morales Ruiz, Juan José (2024-01-01)
      Article
      Accés obert
      In this work we explain the relevance of the Differential Galois Theory in the semiclassical (or WKB) quantification of some two degree of freedom potentials. The key point is that the semiclassical path integral quantification ...
    • Semiclassical theory predicts stochastic ghosts scaling 

      Lázaro Ochoa, José Tomás; Sardanyes Cayuela, Josep; Alarcón, Tomás; Peña Garay, Carlos (Royal Society, 2023-05)
      Article
      Accés restringit per política de l'editorial
      Slowing down occurs in dynamical systems close to bifurcations or phase transitions. The time length (t) of ghost transients close to a saddle-node bifurcation in deterministic systems follows t~|¿-¿c|-1/2, ¿ being the ...
    • Teoria d'àlgebra lineal numèrica 

      Lázaro Ochoa, José Tomás; Ollé Torner, Mercè; Pacha Andújar, Juan Ramón (Universitat Politècnica de Catalunya, 2019-02-28)
      Apunts
      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 

      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 ...
    • Viral replication modes in single-peak fitness landscapes: A dynamical systems analysis 

      Forners, Joan; Lázaro Ochoa, José Tomás; Alarcón, Tomás; Elena, Santiago F.; Sardanyes, Josep (2019-01-07)
      Article
      Accés obert
      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 ...