In this work we consider the Kolmogorov system of degree 3 in R2 and R3 having an equilibrium point in the positive quadrant and octant, respectively. We provide sufficient conditions in order that the equilibrium point will be a Hopf point for the planar case and a zero-Hopf point for the spatial one. We study the limit cycles bifurcating from these equilibria using averaging theory of second and first order, respectively. We note that the equilibrium point is located in the quadrant or octant where the Kolmogorov systems have biological meaning
The paper is devoted to the study of a class of Kolmogorov type systems which can be used to represe...
We study the number of limit cycles bifurcating from the origin of a Hamiltonian system of degree 4....
Agraïments: The second author has been partially supported by FCT through CAMGDS, Lisbon
In this work we consider the Kolmogorov system of degree 3 in R2 and R3 having an equilibrium point ...
A Hopf equilibrium of a differential system in R2 is an equilibrium point whose linear part has eige...
In this work we study the periodic orbits which bifurcate from all zero-Hopf bifurcations that an ar...
The Kolmogorov model is a class of significant ecological models and is initially introduced to desc...
AbstractWe show that for certain cubic Kolmogorov systems, four, and no more than four, limit cycles...
AbstractIn this paper, the general Kolmogorov system {dxdt=ϕ(x)f(x,y),dydt=ρ(y)g(x,y) is studied. By...
AbstractWe consider a class of cubic Kolmogorov systems. We show in particular that a maximum of six...
The main objective of this paper is to study existence and non existence of limit cycles by using th...
In this paper we study the number of limit cycles bifurcating from isochronous surfaces of revolutio...
Using the Andronov-Hopf bifurcation theorem and the Poincaré-Bendixson Theorem, this paper explores ...
In this paper we outline some methods of finding limit cycles for planar autonomous systems with sma...
We study the bifurcation of limit cycles from the periodic orbits of a linear differential system in ...
The paper is devoted to the study of a class of Kolmogorov type systems which can be used to represe...
We study the number of limit cycles bifurcating from the origin of a Hamiltonian system of degree 4....
Agraïments: The second author has been partially supported by FCT through CAMGDS, Lisbon
In this work we consider the Kolmogorov system of degree 3 in R2 and R3 having an equilibrium point ...
A Hopf equilibrium of a differential system in R2 is an equilibrium point whose linear part has eige...
In this work we study the periodic orbits which bifurcate from all zero-Hopf bifurcations that an ar...
The Kolmogorov model is a class of significant ecological models and is initially introduced to desc...
AbstractWe show that for certain cubic Kolmogorov systems, four, and no more than four, limit cycles...
AbstractIn this paper, the general Kolmogorov system {dxdt=ϕ(x)f(x,y),dydt=ρ(y)g(x,y) is studied. By...
AbstractWe consider a class of cubic Kolmogorov systems. We show in particular that a maximum of six...
The main objective of this paper is to study existence and non existence of limit cycles by using th...
In this paper we study the number of limit cycles bifurcating from isochronous surfaces of revolutio...
Using the Andronov-Hopf bifurcation theorem and the Poincaré-Bendixson Theorem, this paper explores ...
In this paper we outline some methods of finding limit cycles for planar autonomous systems with sma...
We study the bifurcation of limit cycles from the periodic orbits of a linear differential system in ...
The paper is devoted to the study of a class of Kolmogorov type systems which can be used to represe...
We study the number of limit cycles bifurcating from the origin of a Hamiltonian system of degree 4....
Agraïments: The second author has been partially supported by FCT through CAMGDS, Lisbon