Ara es mostren els items 12-31 de 55

    • Continua of periodic points for planar integrable rational maps 

      Gasull Embid, Armengol; Llorens, Mireia; Mañosa Fernández, Víctor (Research India Publications, 2016-09)
      Article
      Accés obert
      We present three alternative methodologies to find continua of periodic points with a prescribed period for rational maps having rational first integrals. The first two have been already used by other authors and apply ...
    • Continua of periodic points for planar integrable rational maps. 

      Gasull Embid, Armengol; Llorens, Mireia; Mañosa Fernández, Víctor (2015-11-30)
      Report de recerca
      Accés obert
      We present three alternative methodologies to find continua of periodic points with a prescribed period for rational maps having rational first integrals. The first two have been already used for other authors and apply ...
    • Counting configurations of limit cycles and centers 

      Gasull Embid, Armengol; Guillamon Grabolosa, Antoni; Mañosa Fernández, Víctor (2023-08)
      Article
      Accés obert
      We present several results on the determination of the number and distribution of limit cycles or centers for planar systems of differential equations. In most cases, the study of a recurrence is one of the key points of ...
    • Different approaches to the global periodicity problem 

      Cima Mollet, Anna; Gasull Embid, Armengol; Mañosa Fernández, Víctor; Mañosas, Francesc (2013-07-25)
      Report de recerca
      Accés obert
      t Let F be a real or complex n-dimensional map. It is said that F is globally periodic if there exists some p ∈ N + such that Fp(x) = x for all x, where F k = F ◦ F k−1, k ≥ 2. The minimal p satisfying this property is ...
    • First derivative of the period function with applications 

      Freire, Emilio; Gasull Embid, Armengol; Guillamon Grabolosa, Antoni (2001)
      Article
      Accés obert
      Given a centre of a planar differential system, we extend the use of the Lie bracket to the determination of the monotonicity character of the period function. As far as we know, there are no general methods to study ...
    • Global periodicity conditions for maps and recurrences via Normal Forms 

      Cima Mollet, Anna; Gasull Embid, Armengol; Mañosa Fernández, Víctor (2012-05-04)
      Altres
      Accés obert
      We face the problem of characterizing the periodic cases in parametric families of (real or complex) rational diffeomorphisms having a fixed point. Our approach relies on the Normal Form Theory, to obtain necessary conditions ...
    • Global periodicity conditions for maps and recurrences via normal forms 

      Cima Mollet, Anna; Gasull Embid, Armengol; Mañosa Fernández, Víctor (2013-11)
      Article
      Accés obert
      We face the problem of characterizing the periodic cases in parametric families of rational diffeomorphisms of K, where K is ℝ or ℂ, having a fixed point. Our approach relies on the Normal Form Theory, to obtain necessary ...
    • Identification of one-parameter bifurcations giving rise to periodic orbits, from their period function. 

      Gasull Embid, Armengol; Mañosa Fernández, Víctor; Villadelprat Yagüe, Jordi (Universitat Politècnica de Catalunya. Centre Internacional de Mètodes Numèrics en Enginyeria (CIMNE), 2009)
      Text en actes de congrés
      Accés obert
    • Integrability and non-integrability of periodic non-autonomous Lyness recurrences 

      Cima Mollet, Anna; Gasull Embid, Armengol; Mañosa Fernández, Víctor (2010-12-22)
      Altres
      Accés obert
      This paper studies non-autonomous Lyness type recurrences of the form x_{n+2}=(a_n+x_n)/x_{n+1}, where a_n is a k-periodic sequence of positive numbers with prime period k. We show that for the cases k in {1,2,3,6} the ...
    • Integrability and non-integrability of periodic non-autonomous Lyness recurrences 

      Cima Mollet, Anna; Gasull Embid, Armengol; Mañosa Fernández, Víctor (2013-12-01)
      Article
      Accés obert
      This paper studies non-autonomous Lyness-type recurrences of the form x n+2 = (a n + x n+1)/x n , where {a n } is a k-periodic sequence of positive numbers with primitive period k. We show that for the cases k {1, 2, 3, ...
    • Integrability and non-integrability of periodic non-autonomous Lyness recurrences (revised and enlarged version) 

      Cima Mollet, Anna; Gasull Embid, Armengol; Mañosa Fernández, Víctor (2011-12-22)
      Altres
      Accés obert
      This paper studies non-autonomous Lyness type recurrences of the form xn+2 = (an+xn+1)=xn, where fang is a k-periodic sequence of positive numbers with primitive period k. We show that for the cases k 2 f1; 2; 3; 6g the ...
    • Limit cycles and Lie symmetries 

      Freire, Emilio; Gasull Embid, Armengol; Guillamon Grabolosa, Antoni (2005)
      Article
      Accés obert
      Given a planar vector field U which generates the Lie symmetry of some other vector field X, we prove a new criterion to control the stability of the periodic orbits of U. The problem is linked to a classical problem ...
    • Limit cycles for generalized Abel equations 

      Gasull Embid, Armengol; Guillamon Grabolosa, Antoni (2005)
      Article
      Accés obert
      This paper deals with the problem of finding upper bounds on the number of periodic solutions of a class of one-dimensional non-autonomous differential equations: those with the right-hand sides being polynomials of ...
    • Limit cycles for piecewise linear differential systems via Poincaré–Miranda theorem 

      Gasull Embid, Armengol; Mañosa Fernández, Víctor (Birkhäuser, 2019)
      Capítol de llibre
      Accés restringit per política de l'editorial
      In Gasull and Mañosa (Periodic orbits of discrete and continuous dynamical systems via Poincaré–Miranda theorem, Preprint 2018 Ref [2]), we develop an effective procedure to prove the existence, determine the number, and ...
    • Non autonomous 2-periodic Gumovski-Mira difference equations 

      Cima Mollet, Anna; Gasull Embid, Armengol; Mañosa Fernández, Víctor (2011-06-01)
      Report de recerca
      Accés obert
      We consider two types of non-autonomous 2-periodic Gumovski-Mira difference equations. We show that while the corresponding autonomous recurrences are conjugated, the behavior of the sequences generated by the 2-periodic ...
    • Non-autonomous two periodic Gumovski-Mira difference equations 

      Cima Mollet, Anna; Gasull Embid, Armengol; Mañosa Fernández, Víctor (2012-12)
      Article
      Accés obert
      We consider two types of nonautonomous two-periodic Gumovski–Mira difference equations. We show that while the corresponding autonomous recurrences are conjugated, the behavior of the sequences generated by the two-periodic ...
    • Non-integrability of measure preserving maps via Lie symmetries 

      Cima Mollet, Anna; Gasull Embid, Armengol; Mañosa Fernández, Víctor (2015-03-18)
      Report de recerca
      Accés obert
      We consider the problem of characterizing, for certain natural number m, the local C^m-non-integrability near elliptic fixed points of smooth planar measure preserving maps. Our criterion relates this non-integrability ...
    • Non-integrability of measure preserving maps via Lie symmetries 

      Cima Mollet, Anna; Gasull Embid, Armengol; Mañosa Fernández, Víctor (2015-11-15)
      Article
      Accés obert
      We consider the problem of characterizing, for certain natural number m, the local C^m-non-integrability near elliptic fixed points of smooth planar measure preserving maps. Our criterion relates this non-integrability ...
    • On 2- and 3-periodic Lyness difference equations 

      Cima Mollet, Anna; Gasull Embid, Armengol; Mañosa Fernández, Víctor (2011-06-09)
      Article
      Accés obert
      We describe the sequences {xn}n given by the non-autonomous second-order Lyness difference equations xnþ2 ¼ ðan þ xnþ1Þ=xn, where {an}n is either a 2-periodic or a 3- periodic sequence of positive values and the initial ...
    • On Poncelet's maps 

      Cima Mollet, Anna; Gasull Embid, Armengol; Mañosa Fernández, Víctor (2010-08-08)
      Article
      Accés obert
      Given two ellipses, one surrounding the other one, Poncelet introduced a map P from the exterior one to itself by using the tangent lines to the interior ellipse. This procedure can be extended to any two smooth, nested ...