Transformation invariance of Lyapunov exponents

Lyapunov exponents represent important quantities to characterize the prope rties of dynamical systems. We show that the Lyapunov exponents of two diff erent dynamical systems that can be converted to each other by a transforma tion of variables are identical. Moreover, we derive sufficient conditions on the transformation for this invariance properly to hold. In particular, it turns out that the transformation need not necessarily be globally inver tible. (C) 2001 Elsevier Science Ltd. All rights reserved.