Ara es mostren els items 11-30 de 34

• #### Global periodicity conditions for maps and recurrences via normal forms ﻿

(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 ...
• #### Global periodicity conditions for maps and recurrences via Normal Forms ﻿

(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 ...
• #### Identification of one-parameter bifurcations giving rise to periodic orbits, from their period function. ﻿

(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 ﻿

(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 ﻿

(2010-12-22)
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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 (revised and enlarged version) ﻿

(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 ﻿

(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 ﻿

(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 ...
• #### Non autonomous 2-periodic Gumovski-Mira difference equations ﻿

(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 ﻿

(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 ﻿

(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 ﻿

(2015-11-15)
Article
Accés restringit per política de l'editorial
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 ﻿

(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 ﻿

(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 ...

(2012-03)
Article
Accés obert
• #### On two and three periodic Lyness difference equations ﻿

(2009-12-26)
Report de recerca
Accés obert
We describe the sequences {x_n}_n given by the non-autonomous second order Lyness difference equations x_{n+2}=(a_n+x_{n+1})/x_n, where {a_n}_n is either a 2-periodic or a 3-periodic sequence of positive values and the ...
• #### Parrondo's dynamic paradox for the stability of non-hyperbolic fixed points ﻿

(2017-01-20)
Working paper
Accés obert
We show that for periodic non-autonomous discrete dynamical systems, even when a common fixed point for each of the autonomous associated dynamical systems is repeller, this fixed point can became a local attractor for the ...

(2001)
Article
Accés obert
• #### Phase portrait of Hamiltonian systems with homogeneous nonlinearities ﻿

(1999)
Article
Accés obert
The main goal of this work is to describe the phase portarit of Hamiltonian systems with a non degenerate center at the origin and homogeneous nonlinearities of arbitrary degree n. We apply our results to the case n=2 to ...
• #### Rational periodic sequences for the Lyness recurrence ﻿

(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 ...