title: Comment on "Adaptive-feedback control algorithm".
abstract: We point out a problem in the parametric estimation method based on the adaptive-feedback algorithm proposed by D. Huang [Phys. Rev. E 73, 066204 (2006)] both illustratively and analytically. Furthermore, under some hypotheses, we prove that it is not the so-called chaotic dynamical characteristic but the linear independence between the right-hand functions and the estimated parameters of the intrinsic system in its attractor that counts in the availability of this algorithm in estimating the unknown parameters.
authors.affiliation: Max-Planck-Institute for Mathematics in the Sciences, Inselstr. 22, Leipzig, 04103, Germany. wenlian@mis.mpg.de
authors.forename: Wenlian
authors.initials: W
authors.lastname: Lu