Trace Complexity of Chaotic Reversible Cellular Automata
  Delvenne, K\r{u}rka and Blondel have defined new notions of computational complexity for arbitrary symbolic systems, and shown examples of effective systems that are computationally universal in this sense. The notion is defined in terms of the trace function of the system, and aims to capture its dynamics. We present a Devaney-chaotic reversible cellular automaton that is universal in their sense, answering a question that they explicitly left open. We also discuss some implications and limitations of the construction. 
Jarkko Kari, Ville Salo, Ilkka T\"orm\"a
math.DS cs.FL