Small amplitude limit cycles of polynomial differential equations

Author(s):  
N. G. Lloyd
Author(s):  
T. R. Blows ◽  
N. G. Lloyd

SynopsisTwo-dimensional differential systemsare considered, where P and Q are polynomials. The question of interest is the maximum possible numberof limit cycles of such systems in terms of the degree of P and Q. An algorithm is described for determining a so-called focal basis; this can be implemented on a computer. Estimates can then be obtained for the number of small-amplitude limit cycles. The technique is applied to certain cubic systems; a class of examples with exactly five small-amplitude limit cycles is constructed. Quadratic systems are also considered.


2011 ◽  
Vol 181 (1) ◽  
pp. 461-475 ◽  
Author(s):  
Jaume Giné ◽  
Maite Grau ◽  
Jaume Llibre

2000 ◽  
Vol 43 (3) ◽  
pp. 529-543 ◽  
Author(s):  
Chengzhi Li ◽  
Weigu Li ◽  
Jaume Llibre ◽  
Zhifen Zhang

AbstractWe consider three classes of polynomial differential equations of the form ẋ = y + establish Pn (x, y), ẏ = x + Qn (x, y), where establish Pn and Qn are homogeneous polynomials of degree n, having a non-Hamiltonian centre at the origin. By using a method different from the classical ones, we study the limit cycles that bifurcate from the periodic orbits of such centres when we perturb them inside the class of all polynomial differential systems of the above form. A more detailed study is made for the particular cases of degree n = 2 and n = 3.


Author(s):  
T. R. Blows ◽  
N. G. Lloyd

We consider second order differential equations of Liénard type:Such equations have been very widely studied and arise frequently in applications. There is an extensive literature relating to the existence and uniqueness of periodic solutions: the paper of Staude[6] is a comprehensive survey. Our interest is in the number of periodic solutions of such equations.


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Regilene D. S. Oliveira ◽  
Iván Sánchez-Sánchez ◽  
Joan Torregrosa

AbstractThe present work introduces the problem of simultaneous bifurcation of limit cycles and critical periods for a system of polynomial differential equations in the plane. The simultaneity concept is defined, as well as the idea of bi-weakness in the return map and the period function. Together with the classical methods, we present an approach which uses the Lie bracket to address the simultaneity in some cases. This approach is used to find the bi-weakness of cubic and quartic Liénard systems, the general quadratic family, and the linear plus cubic homogeneous family. We finish with an illustrative example by solving the problem of simultaneous bifurcation of limit cycles and critical periods for the cubic Liénard family.


2014 ◽  
Vol 24 (05) ◽  
pp. 1450065 ◽  
Author(s):  
Jaume Llibre ◽  
Jiang Yu ◽  
Xiang Zhang

We consider the class of polynomial differential equations ẋ = λx + Pn(x, y), ẏ = μy + Qn(x, y) in ℝ2 where Pn(x, y) and Qn(x, y) are homogeneous polynomials of degree n > 1 and λ ≠ μ, i.e. the class of polynomial differential systems with a linear node with different eigenvalues and homogeneous nonlinearities. For this class of polynomial differential equations, we study the existence and nonexistence of limit cycles surrounding the node localized at the origin of coordinates.


1991 ◽  
Vol 47 (2) ◽  
pp. 163-171 ◽  
Author(s):  
E. M. JAMES ◽  
N. G. LLOYD

1996 ◽  
Vol 3 (2) ◽  
pp. 183-190 ◽  
Author(s):  
Colin J. Christopher ◽  
Noel G. Lloyd
Keyword(s):  

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