Resultats globals: 28 registres trobats en 0.02 segons.
Articles, 28 registres trobats
Articles 28 registres trobats  1 - 10següentfinal  anar al registre:
1.
Integrability of a class of N-dimensional Lotka-Volterra and Kolmogorov systems / Llibre, Jaume (Universitat Autònoma de Barcelona. Departament de Matemàtiques) ; Ramírez, Rafael Orlando (Universitat Rovira i Virgili. Departament d'Enginyeria Informàtica i Matemàtiques) ; Ramírez, Valentín (Universitat Autònoma de Barcelona)
We study the integrability of an N-dimensional differential Kolmogorov systems of the form ̇xj=xj(aj+N∑k=1ajkxk)+xjΨ(x1,. . . ,xN), j= 1,. . . ,N, where aj, and ajk are constants for j,k = 1,. . . [...]
2020 - 10.1016/j.jde.2020.02.001
Journal of Differential Equations, Vol. 269, Issue 3 (July 2020) , p. 2503-2531  
2.
15 p, 767.1 KB On the mechanisms for producing linear type centers in polynomial differential systems / Giné, Jaume (Universitat de Lleida. Departament de Matemàtica) ; Llibre, Jaume (Universitat Autònoma de Barcelona. Departament de Matemàtiques)
In this paper we study the different mechanisms that give rise to linear type centers for polynomial differential systems. The known mechanisms are the algebraic reversibility and the Liouville integrability. [...]
2018 - 10.17323/1609-4514-2018-18-3-409-420
Moscow Mathematical Journal, Vol. 18, Issue 3 (July-September 2018) , p. 409-420  
3.
9 p, 686.4 KB Chiellini Hamiltonian Liénard differential systems / Giné, Jaume (Universitat de Lleida. Departament de Matemàtica) ; Llibre, Jaume (Universitat Autònoma de Barcelona. Departament de Matemàtiques) ; Valls, Clàudia 1973- (Universidade de Lisboa. Instituto Superior Técnico. Departamento de Matemática)
We characterize the centers of the Chiellini Hamiltonian Liénard second-order differential equations x′ = y, y′ = −f(x)y−g(x) where g(x) = f(x)(k−α(1 + α)Rf(x)dx) with α,k ∈ R. Moreover we study the phase portraits in the Poincaré disk of these systems when f(x) is linear.
2019
Electronic journal of differential equations, Vol. 2019, Issue 71 (2019) , p. 1-8
2 documents
4.
The center and cyclicity problems for quartic linear-like reversible systems / da Cruz, Leonardo P. C. (Universitat Autònoma de Barcelona. Departament de Matemàtiques) ; Romanovski, Valery G. (University of Maribor. Center for Applied Mathematics and Theoretical Physics (Slovenia)) ; Torregrosa, Joan (Universitat Autònoma de Barcelona. Departament de Matemàtiques)
In this paper we study a family of quartic linear-like reversible polynomial systems having a nondegenerate center at the origin. This family has degree one with respect to one of the variables. We are interested in systems in this class having two extra nondegenerate centers outside the straight line of symmetry. [...]
2020 - 10.1016/j.na.2019.111593
Nonlinear Analysis : Theory, Methods and Applications, Vol. 190 (January 2020) , art. 111593  
5.
The center problem for Z2-symmetric nilpotent vector fields / Algaba, Antonio (Universidad de Huelva. Departamento de Matemáticas) ; García, Cristóbal (Universidad de Huelva. Departamento de Matemáticas) ; Giné, Jaume (Universitat de Lleida. Departament de Matemàtica) ; Llibre, Jaume (Universitat Autònoma de Barcelona. Departament de Matemàtiques)
We say that a polynomial differential system x˙=P(x,y), y˙=Q(x,y) having the origin as a singular point is Z-symmetric if P(−x,−y)=−P(x,y) and Q(−x,−y)=−Q(x,y). It is known that there are nilpotent centers having a local analytic first integral, and others which only have a C first integral. [...]
2018 - 10.1016/j.jmaa.2018.05.079
Journal of mathematical analysis and applications, Vol. 466, Issue 1 (October 2018) , p. 183-198  
6.
Limit cycles in 4-star-symmetric planar piecewise linear systems / Buzzi, Claudio A. (Universidade Estadual Paulista. Departamento de Matemática (Brazil)) ; Medrado, Joao Carlos (Universidade Federal de Goiás. Instituto de Matemática e Estatística (Brazil)) ; Torregrosa, Joan (Universitat Autònoma de Barcelona. Departament de Matemàtiques)
Our interest is centered in the study of the number of limit cycles for nonsmooth piecewise linear vector fields on the plane when the switching curve is xy=0. We consider the symmetric case. That is, one vector field defined in the odd quadrants and the other in the even ones. [...]
2020 - 10.1016/j.jde.2019.09.008
Journal of differential equations, Vol. 268, Issue 5 (February 2020) , p. 2414-2434  
7.
Orbitally universal centers / Algaba, Antonio (Universidad de Huelva. Departamento de Matemáticas) ; García, Cristóbal (Universidad de Huelva. Departamento de Matemáticas) ; Giné, Jaume (Universitat de Lleida. Departament de Matemàtica) ; Llibre, Jaume (Universitat Autònoma de Barcelona. Departament de Matemàtiques)
In this paper we define when a polynomial differential system is orbitally universal and we show the relevance of this notion in the classical center problem, i. e. in the problem of distinguishing between a focus and a center.
2020 - 10.1016/j.na.2020.111746
Nonlinear Analysis : Theory, Methods and Applications, Vol. 195 (June 2020) , art. 111746  
8.
15 p, 363.9 KB Simultaneity of centres in Zq-equivariant systems / Giné, Jaume (Universitat de Lleida. Departament de Matemàtica) ; Llibre, Jaume (Universitat Autonoma de Barcelona. Departament de Matemàtiques) ; Valls, Clàudia 1973- (Instituto Superior Técnico. Departamento de Matemática (Portugal))
We study the simultaneous existence of centres for two families of planar Zq-equivariant systems. First, we give a short review about Zq-equivariant systems. Next, we present the necessary and sufficient conditions for the simultaneous existence of centres for a Z2-equivariant cubic system and for a Z2- equivariant quintic system.
2018 - 10.1098/rspa.2017.0811
Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences, Vol. 474, Issue 2213 (May 2018) , art. 20170811  
9.
47 p, 952.2 KB An inverse approach to the center problem / Llibre, Jaume (Universitat Autònoma de Barcelona. Departament de Matemàtiques) ; Ramírez, Rafael Orlando (Universitat Rovira i Virgili. Departament d'Enginyeria Informàtica i Matemàtiques) ; Ramírez, Valentín (Universitat de Barcelona)
We consider analytic or polynomial vector fields of the form X=(-y+X)∂∂x+(x+Y)∂∂y, where X= X(x, y)) and Y= Y(x, y)) start at least with terms of second order. It is well-known that X has a center at the origin if and only if X has a Liapunov-Poincaré local analytic first integral of the form H=12(x2+y2)+∑j=3∞Hj, where H = H (x, y) is a homogenous polynomial of degree j. [...]
2019 - 10.1007/s12215-018-0342-1
Rendiconti del Circolo Matematico di Palermo, Vol. 68, Issue 1 (April 2019) , p. 29-64  
10.
15 p, 625.2 KB Centers and uniform isochronous centers of planar polynomial differential systems / Llibre, Jaume (Universitat Autònoma de Barcelona. Departament de Matemàtiques) ; Ramírez, Rafael Orlando (Universitat Rovira i Virgili. Departament d'Enginyeria Informàtica i Matemàtiques) ; Ramírez, Valentín (Universitat de Barcelona) ; Sadovskaia, Natalia (Universitat Politècnica de Catalunya. Departament de Matemàtica Aplicada II)
For planar polynomial vector fields of the form \[ (-y X(x,y)) x (x Y(x,y)) y, \] where X and Y start at least with terms of second order in the variables x and y, we determine necessary and sufficient conditions under which the origin is a center or a uniform isochronous centers.
2018 - 10.1007/s10884-018-9672-0
Journal of dynamics and differential equations, Vol. 30, issue 3 (Sep. 2018) , p. 1295-1310  

Articles : 28 registres trobats   1 - 10següentfinal  anar al registre:
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