Depósito Digital de Documentos de la UAB Encontrados 20 registros  1 - 10siguiente  ir al registro: La búsqueda tardó 0.01 segundos. 
1.
12 p, 630.6 KB On the period function in a class of generalized Lotka-Volterra systems / Villadelprat, Jordi (Universitat de Barcelona. Departament de Matemàtica Aplicada i Anàlisi)
In this note, motivated by the recent results of Wang et al. [Wang et al. , Local bifurcations of critical periods in a generalized 2D LV system, Appl. Math. Comput. 214 (2009) 17-25], we study the behaviour of the period function of the center at the point (1,1) of the planar differential system {u' = up(1−vq),v'= μvq(up−1), where p, q, μ ∈ R with pq > 0 and μ > 0. [...]
2010 - 10.1016/j.amc.2010.03.025
Applied Mathematics and Computation, Vol. 216, Issue 7 (June 2010) , p. 1956-1964  
2.
Bicentric quadrilateral central configurations / Llibre, Jaume (Universitat Autònoma de Barcelona. Departament de Matemàtiques) ; Yuan, Pengfei (Southwest University. School of Mathematics and Statistics (China))
A bicentric quadrilateral is a tangential cyclic quadrilateral. In a tangential quadrilateral, the four sides are tangents to an inscribed circle, and in a cyclic quadrilateral the four vertices lie on a circumscribed circle. [...]
2019 - 10.1016/j.amc.2019.06.021
Applied Mathematics and Computation, Vol. 362 (December 2019) , art. 124507  
3.
Differential equations with a given set of solutions / Llibre, Jaume (Universitat Autònoma de Barcelona. Departament de Matemàtiques) ; Ramírez, Rafael Orlando (Universitat Rovira i Virgili. Departament d'Enginyeria Informàtica i Matemàtiques) ; Sadovskaia, Natalia (Universitat Politècnica de Catalunya. Departament de Matemàtica Aplicada II)
The aim of this paper is to study the following inverse problem of ordinary differential equations: For a given set of analytic functions ω={z(t),…,z(t)}, with z(t)=x(t)+iy(t) and z¯(t)=x(t)−iy(t) for j=1,…,r, defined in the open interval I⊆R, we want to determine the differential equation F(t,z¯,z,z˙,z¯˙,…,z,z¯)=0,where [Formula presented] for j=1,…,n, in such a way that the given set of functions ω is a set of solutions of this differential equation.
2020 - 10.1016/j.amc.2019.124659
Applied Mathematics and Computation, Vol. 365 (January 2020) , art. 124659  
4.
31 p, 10.1 MB Trapezoid central configurations / Corbera Subirana, Montserrat (Universitat de Vic. Departament d'Enginyeries) ; Cors Iglesias, Josep Maria (Universitat Politècnica de Catalunya. Departament de Matemàtiques) ; Llibre, Jaume (Universitat Autònoma de Barcelona. Departament de Matemàtiques) ; Pérez-Chavela, Ernesto (UAM-Iztapalapa(México). Departamento de Matemáticas)
We classify all planar four-body central configurations where two pairs of the bodies are on parallel lines. Using cartesian coordinates, we show that the set of four-body trapezoid central configurations with positive masses forms a two-dimensional surface where two symmetric families, the rhombus and isosceles trapezoid, are on its boundary. [...]
2019 - 10.1016/j.amc.2018.10.066
Applied Mathematics and Computation, Vol. 346 (April 2019) , p. 127-142  
5.
13 p, 906.5 KB Newton's method for symmetric quartic polynomials / Campos, Beatriz (Universitat Jaume I(Castelló de la Plana). Departament de Matemàtiques) ; Garijo, Antoni (Universitat Rovira i Virgili. Departament d'Enginyeria Informàtica i Matemàtiques) ; Jarque i Ribera, Xavier (Universitat de Barcelona. Departament de Matemàtica Aplicada i Anàlisi) ; Vindel, Pura (Universitat Jaume I(Castelló de la Plana). Departament de Matemàtiques)
We investigate the parameter plane of the Newton's method applied to the family of quartic polynomials p_a,b(z)=z^4 az^3 bz^2 az 1, where a and b are real parameters. We divide the parameter plane (a,b) R^2 into twelve open and connected regions where p, p' and p'' have simple roots. [...]
2016 - 10.1016/j.amc.2016.06.021
Applied Mathematics and Computation, Vol. 290 (2016) , p. 326-335  
6.
12 p, 584.1 KB Limit cycles bifurcating from the periodic annulus of the weight-homogeneous polynomial centers of weight-degree 2 / Llibre, Jaume (Universitat Autònoma de Barcelona. Departament de Matemàtiques) ; Lopes, Bruno D. (Universitat Autònoma de Barcelona. Departament de Matemàtiques) ; de Moraes, Jaime R. (IBILCE-UNESP(Brazil). Departamento de Matemática)
We obtain an explicit polynomial whose simple positive real roots provide the limit cycles which bifurcate from the periodic orbits of a family of cubic polynomial differential centers when it is perturbed inside the class of all cubic polynomial differential systems. [...]
2016 - 10.1016/j.amc.2015.10.079
Applied Mathematics and Computation, Vol. 274 (2016) , p. 47-54  
7.
9 p, 570.0 KB On the periodic orbit bifurcating from a Hopf bifurcation in systems with two slow and one fast variables / García, Isaac A. (Universitat de Lleida. Departament de Matemàtica) ; Llibre, Jaume (Universitat Autònoma de Barcelona. Departament de Matemàtiques) ; Maza, Susanna (Universitat de Lleida. Departament de Matemàtica)
The Hopf bifurcation in slow-fast systems with two slow variables and one fast variable has been studied recently, mainly from a numerical point of view. Our goal is to provide an analytic proof of the existence of the zero Hopf bifurcation exhibited for such systems, and to characterize the stability or instability of the periodic orbit which borns in such zero Hopf bifurcation. [...]
2014 - 10.1016/j.amc.2013.12.184
Applied Mathematics and Computation, Vol. 232 (2014) , p. 84-90  
8.
50 p, 625.7 KB Central configurations of the 4-body problem with masses m_1=m_2>m_3=m_4=m>0 and m small / Corbera Subirana, Montserrat (Universitat de Vic. Departament de Tecnologies Digitals i de la Informació) ; Llibre, Jaume (Universitat Autònoma de Barcelona. Departament de Matemàtiques)
In this paper we give a complete description of the families of central configurations of the planar 4-body problem with two pairs of equals masses and two equal masses sufficiently small. In particular, we give an analytical proof that this particular 4-body problem has exactly 34 different classes of central configurations. [...]
2014 - 10.1016/j.amc.2014.07.109
Applied Mathematics and Computation, Vol. 246 (2014) , p. 121-147  
9.
21 p, 834.7 KB Centers for a class of generalized quintic polynomial differential systems / Giné, Jaume (Universitat de Lleida. Departament de Matemàtica) ; Llibre, Jaume (Universitat Autònoma de Barcelona. Departament de Matemàtiques) ; Valls, Clàudia 1973- (Universidade Técnica de Lisboa. Departamento de Matemática)
We classify the centers of the polynomial differential systems in R2 of degree d ≥ 5 odd that in complex notation writes as z˙ = iz + (zz¯)d−5/2 (Az5 + Bz4z¯ + Cz3z¯2 + Dz2z¯3 + Ezz¯4 + Fz¯5), where A, B, C, D, E, F ∈ C and either A = Re(D) = 0, or A = Im(D) = 0, or Re(A) = D = 0, or Im(A) = D = 0.
2014 - 10.1016/j.amc.2014.05.047
Applied Mathematics and Computation, Vol. 242 (2014) , p. 187-195  
10.
9 p, 661.1 KB The symmetric central configurations of the 4-body problem with masses m_1=m_2 m_3=m_4 / Álvarez-Ramírez, Martha (UAM-Iztapalapa(México). Departamento de Matemáticas) ; Llibre, Jaume (Universitat Autònoma de Barcelona. Departament de Matemàtiques)
We characterize the planar central configurations of the 4-body problem with masses m1 = m2 ̸= m3 = m4 which have an axis of symmetry. It is known that this problem has exactly two classes of convex central configurations, one with the shape of a rhombus and the other with the shape of an isosceles trapezoid. [...]
2013 - 10.1016/j.amc.2012.12.036
Applied Mathematics and Computation, Vol. 219 (2013) , p. 5996-6001  

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