In this work we study the local cyclicity of some polynomial vector fields in R 3. In particular,
we give a quadratic system with 11 limit cycles, a cubic system with 31 limit cycles, a quartic …

In this paper, Hopf bifurcation and center problem are investigated for a class of more
generalized Lorenz systems, which are Z 2 symmetric and quadratic three-dimensional …

Our main goal in this paper is to study the number of small-amplitude isolated periodic
orbits, so-called limit cycles, surrounding only one equilibrium point a class of polynomial …

In this paper, Hopf bifurcation and center problem for a generic three‐dimensional Chua's
circuit system are studied. Applying the formal series method of computing singular point …

This work provides upper bounds on the cyclicity of the centers on center manifolds in the
well-known Lorenz family, and also in the Chen and Lü families. We prove that at most one …

We consider quadratic three-dimensional differential systems having a Hopf singular point.
We study their cyclicity when the singular point is a center on the center manifold using …

We consider three-dimensional polynomial families of vector fields parameterized by the
admissible coefficients having a fixed zero-Hopf equilibrium and a non-singular rotation axis …

Neste trabalho, estudamos o Problema do Centro-Foco para sistemas planares e sua
extensão para sistemas tridimensionais apresentando alguns dos resultados mais recentes …

This paper focuses on investigating the bifurcation of limit cycles and centers within a
specific class of three-dimensional cubic systems possessing Z 3-equivariant symmetry. By …

In this paper, Hopf and zero-Hopf bifurcations are investigated for a class of three-
dimensional cubic Kolmogorov systems with one positive equilibrium. Firstly, by computing …