scholarly journals Perturbation theory of the quadratic Lotka–Volterra double center

2021 ◽  
Author(s):  
Jean–Pierre Françoise ◽  
Lubomir Gavrilov
Keyword(s):  
Perturbation Theory ◽  
Limit Cycles ◽  
Bifurcation Theory ◽  
Path Integrals ◽  
Quadratic System ◽  
Finite Plane

We revisit the bifurcation theory of the Lotka–Volterra quadratic system [Formula: see text] with respect to arbitrary quadratic deformations. The system has a double center, which is moreover isochronous. We show that the deformed system can have at most two limit cycles on the finite plane, with possible distribution [Formula: see text], where [Formula: see text]. Our approach is based on the study of pairs of bifurcation functions associated to the centers, expressed in terms of iterated path integrals of length two.

scholarly journals Quadratic systems with a weak focus

1991 ◽  
Vol 44 (3) ◽  
pp. 511-526 ◽  
Author(s):  
Zhang Pingguang ◽  
Cai Suilin
Keyword(s):  
Singular Point ◽  
Limit Cycle ◽  
Limit Cycles ◽  
Relative Position ◽  
Quadratic System ◽  
Singular Points ◽  
Finite Plane ◽  
Quadratic Systems ◽  
Weak Focus

In this paper we study the number and the relative position of the limit cycles of a plane quadratic system with a weak focus. In particular, we prove the limit cycles of such a system can never have (2, 2)-distribution, and that there is at most one limit cycle not surrounding this weak focus under any one of the following conditions:(i) the system has at least 2 saddles in the finite plane,(ii) the system has more than 2 finite singular points and more than 1 singular point at infinity,(iii) the system has exactly 2 finite singular points, more than 1 singular point at infinity, and the weak focus is itself surrounded by at least one limit cycle.

scholarly journals Perturbation theory for path integrals of stiff polymers

2006 ◽  
Vol 39 (26) ◽  
pp. 8231-8255 ◽  
Author(s):  
H Kleinert ◽  
A Chervyakov
Keyword(s):  
Perturbation Theory ◽  
Path Integrals

scholarly journals On acyclicity of quadratic system with two non-rough foci

2021 ◽  
pp. 41-46
Author(s):  
Адам Дамирович Ушхо
Keyword(s):  
Differential Equations ◽  
Limit Cycles ◽  
Phase Plane ◽  
Second Order ◽  
Quadratic System ◽  
Equilibrium States ◽  
System Of Differential Equations ◽  
Right Hand ◽  
The Right

Доказывается, что система дифференциальных уравнений, правые части которой представляют собой полиномы второй степени, не имеет предельных циклов, если в ограниченной части фазовой плоскости она имеет только два состояния равновесия и при этом они являются состояниями равновесия второй группы. It is proved that a system of differential equations, the right-hand sides of which are second-order polynomials, has no limit cycles if it has only two equilibrium states in the bounded part of the phase plane, and they are the equilibrium states of the second group.

Canard explosion, homoclinic and heteroclinic orbits in singularly perturbed generalist predator–prey systems

2020 ◽  
pp. 2150003
Author(s):  
Ali Atabaigi
Keyword(s):  
Perturbation Theory ◽  
Singular Perturbation ◽  
Limit Cycles ◽  
Heteroclinic Orbits ◽  
Singular Perturbation Theory ◽  
Geometric Singular Perturbation Theory ◽  
Generalist Predator ◽  
Normal Form Theory ◽  
Predator Prey ◽  
Geometric Singular Perturbation

This paper studies the dynamics of the generalist predator–prey systems modeled in [E. Alexandra, F. Lutscher and G. Seo, Bistability and limit cycles in generalist predator–prey dynamics, Ecol. Complex. 14 (2013) 48–55]. When prey reproduces much faster than predator, by combining the normal form theory of slow-fast systems, the geometric singular perturbation theory and the results near non-hyperbolic points developed by Krupa and Szmolyan [Relaxation oscillation and canard explosion, J. Differential Equations 174(2) (2001) 312–368; Extending geometric singular perturbation theory to nonhyperbolic points—fold and canard points in two dimensions, SIAM J. Math. Anal. 33(2) (2001) 286–314], we provide a detailed mathematical analysis to show the existence of homoclinic orbits, heteroclinic orbits and canard limit cycles and relaxation oscillations bifurcating from the singular homoclinic cycles. Moreover, on global stability of the unique positive equilibrium, we provide some new results. Numerical simulations are also carried out to support the theoretical results.

HOPF BIFURCATIONS FOR NEAR-HAMILTONIAN SYSTEMS

2009 ◽  
Vol 19 (12) ◽  
pp. 4117-4130 ◽  
Author(s):  
MAOAN HAN ◽  
JUNMIN YANG ◽  
PEI YU
Keyword(s):  
Hamiltonian Systems ◽  
Limit Cycles ◽  
Efficient Algorithm ◽  
Hamiltonian Function ◽  
Melnikov Function ◽  
Quadratic System ◽  
New Method ◽  
Hopf Bifurcations ◽  
Computationally Efficient ◽  
Bifurcation Of Limit Cycles

In this paper, we consider bifurcation of limit cycles in near-Hamiltonian systems. A new method is developed to study the analytical property of the Melnikov function near the origin for such systems. Based on the new method, a computationally efficient algorithm is established to systematically compute the coefficients of Melnikov function. Moreover, we consider the case that the Hamiltonian function of the system depends on parameters, in addition to the coefficients involved in perturbations, which generates more limit cycles in the neighborhood of the origin. The results are applied to a quadratic system with cubic perturbations to show that the system can have five limit cycles in the vicinity of the origin.

QUALITATIVE ANALYSIS FOR THE MERKIN ENZYME REACTION SYSTEM

2002 ◽  
Vol 10 (02) ◽  
pp. 167-182
Author(s):  
YUQUAN WANG ◽  
ZUORUI SHEN
Keyword(s):  
Hopf Bifurcation ◽  
Limit Cycles ◽  
Local Stability ◽  
Bifurcation Theory ◽  
Sufficient Conditions ◽  
Reaction System ◽  
Enzyme Reaction ◽  
Qualitative Theory ◽  
Positive Equilibrium ◽  
Hopf Bifurcations

Applying qualitative theory and Hopf bifurcation theory, we detailedly discuss the Merkin enzyme reaction system, and the sufficient conditions derived for the global stability of the unique positive equilibrium, the local stability of three equilibria and the existence of limit cycles. Meanwhile, we show that the Hopf bifurcations may occur. Using MATLAB software, we present three examples to simulate these conclusions in this paper.

SMALL LIMIT CYCLES BIFURCATING FROM Z4-EQUIVARIANT NEAR-HAMILTONIAN SYSTEM OF DEGREES 9 AND 7

2012 ◽  
Vol 22 (11) ◽  
pp. 1250272 ◽  
Author(s):  
XIANBO SUN ◽  
JUNMIN YANG
Keyword(s):  
Hopf Bifurcation ◽  
Hamiltonian System ◽  
Limit Cycles ◽  
Bifurcation Theory

In this paper, we study the number and distribution of small limit cycles of some Z4-equivariant near-Hamiltonian system of degree 9. Using the methods of Hopf bifurcation theory, we find that this system can have 64 small limit cycles. The configuration of 64 small limit cycles of the system is also illustrated in Fig. 1. When we let some parameters be zero, then we find that there can be 40 small limit cycles in a seventh system.

BIFURCATIONS OF LIMIT CYCLES IN A Z2-EQUIVARIANT PLANAR POLYNOMIAL VECTOR FIELD OF DEGREE 7

2006 ◽  
Vol 16 (04) ◽  
pp. 925-943 ◽  
Author(s):  
JIBIN LI ◽  
MINGJI ZHANG ◽  
SHUMIN LI
Keyword(s):  
Vector Field ◽  
Dynamical Systems ◽  
Limit Cycles ◽  
Bifurcation Theory ◽  
Vector Fields ◽  
Compound Eyes ◽  
Polynomial Vector ◽  
Polynomial Vector Fields ◽  
Planar Dynamical Systems ◽  
Equivariant Vector Field

By using the bifurcation theory of planar dynamical systems and the method of detection functions, the bifurcations of limit cycles in a Z2-equivariant planar perturbed Hamiltonian polynomial vector fields of degree 7 are studied. An example of a special Z2-equivariant vector field having 50 limit cycles with a configuration of compound eyes are given.

ON THE NUMBER AND DISTRIBUTION OF LIMIT CYCLES IN A CUBIC SYSTEM

2004 ◽  
Vol 14 (12) ◽  
pp. 4285-4292 ◽  
Author(s):  
MAOAN HAN ◽  
TONGHUA ZHANG ◽  
HONG ZANG
Keyword(s):  
Qualitative Analysis ◽  
Limit Cycles ◽  
Bifurcation Theory ◽  
Cubic System

This paper concerns the number of limit cycles in a cubic system. Eleven limit cycles are found and two different distributions are given by using the methods of bifurcation theory and qualitative analysis.

Bifurcations in a Cubic System with a Degenerate Saddle Point

2014 ◽  
Vol 24 (11) ◽  
pp. 1450144
Author(s):  
Desheng Shang ◽  
Yaoming Zhang
Keyword(s):  
Perturbation Theory ◽  
Qualitative Analysis ◽  
Saddle Point ◽  
Limit Cycles ◽  
Blow Up ◽  
Cubic System ◽  
Cubic Systems

Bifurcations in a cubic system with a degenerate saddle point are investigated using the technique of blow-up, the method of planar perturbation theory and qualitative analysis. It has been found that after appropriate perturbations, at least 12 limit cycles can bifurcate from a degenerate saddle point in a type of cubic systems.

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