Cellular Automata and Artiicial Life | Computation and Life in Reversible Cellular Automata |

In this paper, we investigate and discuss the problem how the abilities of computing and self-reproduction can be realized in a \reversible" environment, especially in reversible cellular automata (RCA). An RCA is a \backward deterministic" CA in which every conngu-ration of the cellular space has at most one predecessor. Such systems have a close connection to physical reversibility, and have been known to play an important role in the problem of inevitable power dissipation in computing systems. This problem will become much more important when one tries to construct nano-scaled functional objects based on microscopic physical law. We rst discuss how computation-universality can be obtained under the re-versibility constraint, and show our models of one-and two-dimensional universal RCAs. Next, we explain a self-reproducing model on a two-dimensional RCA and its mechanism. Our new attempt of creating a three-dimensional self-reproducing RCA is also stated.