Comment on ‘‘Suppression of chaos by resonant parametric perturbations’’

The inhibition of the chaotic behavior of the Duffing-Holmes oscillator by means of a small parametric perturbation of suitable frequency, as shown by Lima and Pettini [Phys. Rev. A 41, 726 (1990)], is here reconsidered. The discrepancies noted in that article between the analytical (Melnikov method) and numerical (Lyapunov exponents) results are shown to be basically due to an error in the calculation of the Melnikov distance rather than simply to the method's perturbative nature.