Ara es mostren els items 1-20 de 34

• A characterization of isochronous centres in terms of symmetries ﻿

(2000)
Article
Accés obert
We present a description of isochronous centres of planar vector fields $X$ by means of their groups of symmetries. More precisely, given a normalizer $U$ of $X$ (i.e., $[X,U]=\mu X$, where $\mu$ is a scalar function), we ...
• An analytic-numerical method of computation of the Liapunov and period constants derived from their algebraic structure ﻿

(1996)
Article
Accés obert
We consider the problem of computing the Liapunov and the period constants for a smooth differential equation with a non degenerate critical point. First, we investigate the structure of both constants when they are ...
• An explicit expression of the first Liapunov and period constants with applications ﻿

(1996)
Article
Accés obert
In this paper, we study systems in the plane having a critical point with pure imaginary eigenvalues, and we search for effective conditions to discern whether this critical point is a focus or a center; in the case of it ...
• Basin of attraction of triangular maps with applications ﻿

(2013-07-25)
Report de recerca
Accés obert
We consider some planar triangular maps. These maps preserve certain fibration of the plane. We assume that there exists an invariant attracting fiber and we study the limit dynamics of those points in the basin of attraction ...
• Basin of attraction of triangular maps with applications ﻿

(2014-03)
Article
Accés obert
We consider planar triangular maps that preserve certain fibration of the plane. We assume that there exists an invariant attracting fiber and we study the limit dynamics of those points in the basin of attraction of ...
• Centre and isochronicity conditions for systems with homogeneous nonlinearities ﻿

(1995)
Article
Accés obert
We study the centre-focus problem for systems with homogeneous nonlinearities. In the centre case we study the characterization of the isochronous centres. More explicitly, we derive six necessary conditions to be a ...
• Continua of periodic points for planar integrable rational maps ﻿

(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. ﻿

(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 ...
• Different approaches to the global periodicity problem ﻿

(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 ﻿

(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 ﻿

(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)
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 (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 ...