Solution of some conjectures about topological properties of linear cellular automata

We study two dynamical properties of linear D-dimensional cellular automata over Zm namely, denseness of periodic points and topological mixing. For what concerns denseness of periodic points, we complete the work initiated in (Theoret. Comput. Sci. 174 (1997) 157, Theoret. Comput. Sci. 233 (1–2) (2000) 147, 14th Annual Symp. on Theoretical Aspects of Computer Science (STACS ’97), LNCS n. 1200, Springer, Berlin, 1997, pp. 427–438) by proving that a linear cellular automata has dense periodic points over the entire space of con7gurations if and only if it is surjective (as conjectured in (Cattaneo et al., 2000)). For non-surjective linear CA we give a complete characterization of the subspace where periodic points are dense. For what concerns topological mixing, we prove that this property is equivalent to transitivity and then easily checkable. Finally, we classify linear cellular automata according to the de7nition of chaos given by Devaney in (An Introduction to Chaotic Dynamical Systems, 2nd ed., Addison-Wesley, Reading, MA, USA, 1989). c © 2004 Elsevier B.V. All rights reserved.