ABSTRACT: We critique the measure of complexity introduced by Shiner, Davison, and Landsberg in Ref. [1]. In particular, we point out that it is over-universal, in the sense that it has the same dependence on disorder for structurally distinct systems. We then give counterexamples to the claim that complexity is synonymous with being out of equilibrium: equilibrium systems can be structurally complex and nonequilibrium systems can be structurally simple. We also correct a misinterpretation of a result given by two of the present authors in Ref. [2].
[1] J. S. Shiner, M. Davison, and P. T. Landsberg, "Simple Measure for
Complexity", Phys. Rev. E 59 (1999) 1459-1464.
[2] J. P. Crutchfield and D. P. Feldman, "Statistical Complexity of Simple
One-Dimensional Spin Systems", Phys. Rev. E 55:2 (1997) 1239R-1243R.