Narrow Results

This paper introduces and analyzes new hyperchaotic complex Lorenz systems. These systems are 6-dimensional systems of real first order autonomous differential equations and their dynamics are very complicated and rich. In this study we extend the idea of adding state feedback control and introduce the complex periodic forces to generate hyperchaotic behaviors. The fractional Lyapunov dimension of the hyperchaotic attractors of these systems is calculated. Bifurcation analysis is used to demonstrate chaotic and hyperchaotic behaviors of our new systems. Dynamical systems where the main variables are complex appear in many important fields of physics and communications.

In this paper, Lü system with a set of chaotic parameters is proved to be smoothly nonequivalent to Chen and Lorenz systems with any parameter. The analytical formula for the upper bound of Lyapunov dimension of attractors in Lorenz-type systems are presented under some suitable parameter conditions. These properties studied in this paper may contribute to a better understanding of the Lorenz-type systems.

New classes of Lyapunov-type functions are suggested for the estimation of Lyapunov dimension of Lorenz-like systems. Lyapunov dimension formulas for Lorenz and Tigan systems are obtained.