Cellular automata are a simple model of parallel computation. Many people wonder about the computing power of such a model. Following an idea of S. Wolfram [16], M. Cook [3] has proved than even one of the simplest cellular automata can embed any Turing computation. In this paper, we give a new high-level version of this proof using particles and collisions as introduced in [10]. Introduced in ...

In this paper we highlight the important contribution made by Bob Madix to the understanding of catalysis at single crystal surfaces, focusing here on a favourite model system of his, namely the oxidation of methanol on Cu(110). Madix showed clearly that the methoxy was the pivotal intermediate involved, and it is bound to the surface through the oxygen atom. Here we demonstrate the nature of t...

Elementary cellular automaton (ECA) rules 9 and 74, members of Chua’s Bernoulli shift rules and Wolfram’s class 2, can generate a host of gliders and complicated glider collisions by introducing the hybrid mechanism. These gliders and collisions are more plentiful than those generated by ECA rule 110. This paper presents a discussion of the symbolic dynamics of the gliders in hybrid cellular au...