Projecte

General

Perfil

Tasca #3339 » mostraTorregrosa.txt

Tomas Fabregat, 25-06-2015 11:11

 
type: Article
aigaionid: 4191
bibtexid: CorCorLliMoe2015
title: Bifurcation of relative equilibria of the (1'3)-body problem
author: Corbera, Montserrat
author: Cors, Josep Maria
author: Llibre, Jaume
author: Moeckel, Richard
journal: SIAM Journal on Mathematical Analysis
year: 2015
volume: 47
number: 2
startpage: 1377
endpage: 1404
doi: 10.1137/140978661
keywords: (1 n)-body problem
keywords: Celestial Mechanics
keywords: relative equilibria
abstract: We study the relative equilibria of the limit case of the planar Newtonian 4-body problem when three masses tend to zero, the so-called (1 3)-body problem. Depending on the values of the infinitesimal masses the number of relative equilibria varies from ten to fourteen. Six of these relative equilibria are always convex, and the others are concave. Each convex relative equilibrium of the (1 3)-body problem can be continued to a unique family of relative equilibria of the general 4-body problem when three of the masses are sufficiently small and every convex relative equilibrium for these masses belongs to one of these six families.
file: CorCorLliMoe2015.Preprint.pdf


type: Article
aigaionid: 4183
bibtexid: CanFagGar2015
title: On a Family of Rational Perturbations of the Doubling Map
author: Canela, Jordi
author: Fagella, Nuria
author: Garijo, Antoni
journal: Journal of Difference Equations and Applications
year: 2015
doi: 10.1080/10236198.2015.1050387
keywords: Blaschke products
keywords: circle maps
keywords: Holomorphic dynamics
keywords: polynomial-like mappings
file: CanFagGar2015.preprint.pdf


type: Article
aigaionid: 4178
bibtexid: Gas2015b
title: L?infinit i m?s enll?
author: Gasull, Armengol
journal: Materials Matem?tics
year: 2015
volume: 2015
file: Gas2015b.preprint.pdf


type: Article
aigaionid: 4177
bibtexid: CimGasMan2015
title: Non-integrability of measure preserving maps via {L}ie symmetries
author: Cima, Anna
author: Gasull, Armengol
author: Ma?osa, V?ctor
journal: Journal of Differential Equations
year: 2015
keywords: Cohen map
keywords: difference equations
keywords: Integrability and non-integrability of maps
keywords: integrable vector fields
keywords: Isochronous center
keywords: Lie symmetries
keywords: measure preserving maps
keywords: Period function
abstract: 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 with the existence of some Lie Symmetries associated to the maps, together with the study of the finiteness of its periodic points. One of the steps in the proof uses the regularity of the period function on the whole period annulus for non-degenerate centers, question that we believe that is interesting by itself. The obtained criterion can be applied to prove the local non-integrability of the Cohen map and of several rational maps coming from second order difference equations.
file: CimGasMan2015.preprint.pdf


type: Article
aigaionid: 4176
bibtexid: GraLli2015
title: Divergence and {P}oincar?-{L}iapunov constants for analytic differential systems
author: Grau, Maite
author: Llibre, Jaume
journal: Journal of Differential Equations
year: 2015
volume: 258
startpage: 4348
endpage: 4367
doi: 10.1016/j.jde.2015.01.035
keywords: Center problem
keywords: divergence
keywords: Hamiltonian
keywords: Poincar?-Liapunov constants
abstract: We consider a planar autonomous real analytic differential system with a monodromic singular point $p$. We deal with the center problem for the singular point $p$. Our aim is to highlight some relations between the divergence of the system and the Poincar\'e-Liapunov constants of $p$ when these are defined.
file: GraLli2015.preprint.pdf


type: Article
aigaionid: 4160
bibtexid: FedPan2014
title: The {P}icard-{F}uchs equations for complete hyperelliptic integrals of even order curves, and the actions of the generalized {N}eumann system
author: Fedorov, Yuri
author: Pantazi, Chara
journal: Journal of Mathematical Physics
year: 2014
volume: 55
startpage: 032703
doi: 10.1063/1.4868965
abstract: We consider a family of genus 2 hyperelliptic curves of even order and obtain explicitly the systems of 5 linear ordinary differential equations for periods of the corresponding Abelian integrals of first, second, and third kind, as functions of some parameters of the curves. The systems can be regarded as extensions of the well-studied Picard-Fuchs equations for periods of complete integrals of first and second kind on odd hyperelliptic curves. The periods we consider are linear combinations of the action variables of several integrable systems, in particular the generalized Neumann system with polynomial separable potentials. Thus the solutions of the extended Picard-Fuchs equations can be used to study various properties of the actions.
file: FedPan2014.preprint.pdf


type: Article
aigaionid: 4152
bibtexid: Cau2015
title: Bifurcation of the separatrix skeleton in some 1-parameter families of planar vector fields
author: Caubergh, Magdalena
journal: Journal of Differential Equations
year: 2015
volume: 259
startpage: 989
endpage: 1013
doi: 10.1016/j.jde.2015.02.036
keywords: global phase portrait
keywords: Hilbert?s 16th Problem
keywords: Limit cycle
keywords: nilpotent center problem
keywords: rotated vector field
keywords: separatrix skeleton
abstract: This article deals with the bifurcation of polycycles and limit cycles within the 1-parameter families of planar vector fields $X_m^k,$ defined by $\dot{x}=y^3-x^{2k 1},\dot{y}=-x my^{4k 1},$ where $m$ is a real parameter and $k\ge1$ integer. The bifurcation diagram for the separatrix skeleton of $X_m^k$ in function of $m$ is determined and the one for the global phase portraits of $(X^1_m)_{m\in\mathbb{R}}$ is completed. Furthermore for arbitrary $k\ge1$ some
bifurcation and finiteness problems of periodic orbits are solved. Among others, the number of periodic orbits of $X_m^k$ is found to be uniformly bounded independent of $m\in\mathbb{R}$ and the Hilbert number for $(X_m^k)_{m\in\mathbb{R}},$ that thus is finite, is found to be at least one.
file: Cau2015.preprint.pdf


type: Article
aigaionid: 4151
bibtexid: LiaLliTor2015
title: Limit cycles coming from some uniform isochronous centers
author: Liang, Haihua
author: Llibre, Jaume
author: Torregrosa, Joan
journal: Advanced Nonlinear Studies
year: 2015
keywords: averaging theory
keywords: periodic solution
keywords: uniform isochronous centers
keywords: weak Hilbert problem
abstract: This article is about the weak 16--th Hilbert problem, i.e. we analyze how many limit cycles can bifurcate from the periodic orbits of a given polynomial differential center when it is perturbed
inside a class of polynomial differential systems. More precisely, we consider the uniform isochronous centers
\[
\dot x= -y x^2 y (x^2 y^2)^n, \dot y= x x y^2 (x^2 y^2)^n,
\]
of degree $2n 3$ and we perturb them inside the class of all polynomial differential systems of degree $2n 3$. For $n=0,1$ we provide the maximum number of limit cycles, 3 and 8 respectively, that can bifurcate from the periodic orbits of these centers using averaging theory of first order, or equivalently Abelian integrals. For $n=2$ we show that at least 12 limit cycles can bifurcate from the periodic orbits of the center.
file: LiaLliTor2015.Preprint.pdf


type: Article
aigaionid: 4149
bibtexid: LliVal2015a
title: The co-circular central configurations of the 5 body problem
author: Llibre, Jaume
author: Valls, Cl?udia
journal: Journal of Dynamics and Differential Equations
year: 2015
volume: 27
startpage: 55
endpage: 67
doi: 10.1007/s10884-015-9429-y
keywords: 5-body problem
keywords: Central configuration
keywords: Co-circular central configuration
keywords: Regular n-gon
abstract: Chenciner in 2001 asked: Is the regular n?gon with equal masses the unique central configuration such that all the bodies lie on a circle, and the center of mass coincides with the center of the circle? This question has a positive answer for n = 3. Hampton in 2003 proved that also this question has a positive answer for n = 4. Here we provide a positive answer for n = 5.
file: LliVal2015a.Preprint.pdf


type: Article
aigaionid: 4148
bibtexid: AlvLabMur2014
title: Limit cycles for a class of quintic $\mathbb {Z}_6$ equivariant systems without infinite critical points
author: ?lvarez, Maria Jes?s
author: Laboriau, Isabel S.
author: Murza, Adrian
journal: Bulletin of the Belgian Mathematical Society. Simon Stevin
year: 2014
volume: 21
startpage: 841
endpage: 857
keywords: Limit cycles
keywords: Planar autonomous ordinary differential equations
keywords: symmetric polinomial systems
abstract: We analyze the dynamics of a class of $\mathbb{Z}_6$-equivariant systems of the form $\dot{z}=pz^2\bar{z} sz^3\bar{z}^2-\bar{z}^{5},$ where $z$ is complex, the time $t$ is real, while $p$ and $s$
are complex parameters. This study is the natural continuation of a previous work (M.J. \'Alvarez, A. Gasull, R. Prohens, Proc. Am. Math. Soc. \textbf{136}, (2008), 1035--1043) on the normal form of $\mathbb{Z}_4$-equivariant systems. Our study uses the reduction of the equation to an Abel one,
and provide criteria for proving in some cases uniqueness and hyperbolicity of the limit cycle surrounding either 1, 7 or 13 critical points, the origin being always one of these points.
file: AlvLabMur2014.Preprint.pdf


type: Article
aigaionid: 4147
bibtexid: GeyVil2015
title: On the wave length of smooth periodic traveling waves of the {C}amassa-{H}olm equation
author: Geyer, Anna
author: Villadelprat, Jordi
journal: Journal of Differential Equations
year: 2015
volume: 259
startpage: 2317
endpage: 2332
doi: http://dx.doi.org/10.1016/j.jde.2015.03.027
abstract: This paper is concerned with the wave length $\lambda$ of smooth periodic traveling wave solutions of the Camassa-Holm equation. The set of these solutions can be parametrized using the wave height $a$ (or ``peak-to-peak amplitude''). Our main result establishes monotonicity properties of the map $a\longmapsto \lambda(a)$, i.e., the wave length as a function of the wave height. We obtain the explicit bifurcation values, in terms of the parameters associated to the equation, which distinguish between the two possible qualitative behaviours of $\lambda(a)$, namely monotonicity and unimodality. The key point is to relate $\lambda(a)$ to the period function of a planar differential system with a quadratic-like first integral, and to apply a criterion which bounds the number of critical periods for this type of systems.
file: GeyVil2015.Preprint.pdf


type: Article
aigaionid: 4144
bibtexid: Gas2015
title: B?tes i barrils
author: Gasull, Armengol
journal: Nou Biaix
year: 2015
file: Gas2015.Preprint.pdf


type: Article
aigaionid: 4143
bibtexid: LliPes2015
title: The {H}opf bifurcation in the {S}himizu-{M}orioka system
author: Llibre, Jaume
author: Pessoa, Claudio
journal: Nonlinear Dynamics. An International Journal of Nonlinear Dynamics and Chaos in Engineering Systems
year: 2015
volume: 79
startpage: 2197
endpage: 2205
doi: 10.1007/s11071-014-1805-3
keywords: bifurcation diagram
keywords: Hopf bifurcation
keywords: Limit cycles
file: LliPes2015.Preprint.pdf


type: Article
aigaionid: 4135
bibtexid: ArtLliSchVul2015
title: Global configurations of singularities for quadratic differential systems with exactly three finite singularities of total multiplicity four
author: Art?s, Joan Carles
author: Llibre, Jaume
author: Schlomiuk, Dana
author: Vulpe, Nicolae
journal: The Rocky Mountain Journal of Mathematics
year: 2015
volume: 45
number: 1
startpage: 29
endpage: 113
keywords: affine invariant polynomials
keywords: configuration of singularities
keywords: geometric equivalence relation
keywords: infinite and finite singularities
keywords: Poincar? compactification
keywords: Quadratic vector fields
abstract: In the topological classification of phase portraits no distinctions are made between a focus and a node and neither are they made between a strong and a weak focus or between foci of different orders. These distinction are however important in the production of limit cycles close to the foci in perturbations of the systems. The distinction between the one direction node and the two directions node, which plays a role in understanding the behavior of solution curves around the singularities at infinity, is also missing in the
topological classification.

In this work we introduce the notion of \textit{geometric equivalence relation of singularities} which incorporates these important purely algebraic features. The \textit{geometric} equivalence relation is finer than the \textit{topological} one and also finer than the \textit{qualitative equivalence relation} introduced in \cite{J_L}. We also list all possibilities we have for singularities finite and infinite taking into consideration these finer distinctions and introduce notations for each one of them. Our long term goal is to use this finer equivalence relation to classify the quadratic family according to their different \textit{geometric configurations of singularities}, finite and infinite.

In this work we accomplish a first step of this larger project. We give a complete global classification, using the \textit{geometric equivalence} relation, of the whole quadratic class according to the configuration of singularities at infinity of the systems. Our classification theorem is stated in terms of invariant polynomials and hence it can be applied to any family of quadratic systems with respect to any particular normal form. The theorem we give also contains the bifurcation diagram, done in the 12-parameter space, of
the \textit{geometric configurations} of singularities at infinity, and this bifurcation set is algebraic in the parameter space. To determine the bifurcation diagram of configurations of singularities at infinity for any family of quadratic systems, given in any normal form, becomes thus a simple task using computer algebra
calculations.
file: ArtLliSchVul2015.preprint.pdf


type: Article
aigaionid: 4130
bibtexid: EuzLli2015
title: On the number of limit cycles in discontinuous piecewise linear differential systems with two pieces separated by a straight line
author: D. Euz?bio, Rodrigo
author: Llibre, Jaume
journal: Journal of Mathematical Analysis and Applications
year: 2015
volume: 424
startpage: 475
endpage: 486
doi: 10.1016/j.jmaa.2014.10.077
keywords: Limit cycle
keywords: nonsmooth differential system
keywords: piecewise linear differential system
file: EuzLli2015.preprint.pdf


type: Article
aigaionid: 4127
bibtexid: LliLopMor2015
title: Limit cycles of cubic polynomial differential systems with rational first integrals of degree 2
author: Llibre, Jaume
author: Lopes, Bruno D.
author: de Moraes, Jaime R.
journal: Applied Mathematics and Computation
year: 2015
volume: 250
startpage: 887
endpage: 907
doi: 10.1016/j.amc.2014.11.029
keywords: Averaging method
keywords: Isochronous center
keywords: Limit cycles
keywords: periodic orbits
keywords: Polynomial vector fields
file: LliLopMor2015.Preprint.pdf


type: Article
aigaionid: 4126
bibtexid: ArtRezOli2014a
title: The geometry of quadratic polynomial differential systems with a finite and an infinite saddle-node (C)
author: Art?s, Joan Carles
author: Rezende, Alex Carlucci
author: Oliveira, Regilene D. S.
journal: International Journal of Bifurcation and Chaos in Applied Sciences and Engineering
year: 2015
keywords: algebraic invariants
keywords: bifurcation diagram
keywords: finite saddle-node
keywords: infinite saddle-node
keywords: Phase portrait
keywords: Quadratic differential systems
file: ArtRezOli2014a.preprint.pdf


type: Article
aigaionid: 4125
bibtexid: ArtLliRezSchVul2014
title: Global configurations of singularities for quadratic differential systems with exactly two finite singularities of total multiplicity four
author: Art?s, Joan Carles
author: Llibre, Jaume
author: Rezende, Alex Carlucci
author: Schlomiuk, Dana
author: Vulpe, Nicolae
journal: Electronic Journal of Qualitative Theory of Differential Equations
year: 2014
volume: 60
startpage: 1
endpage: 43
keywords: affine invariant polynomials
keywords: configuration of singularities
keywords: geometric equivalence relation
keywords: infinite and finite singularities
keywords: Poincar? compactification
keywords: Quadratic vector fields
file: ArtLliRezSchVul2014.preprint.pdf
(1-1/5)