On Finite 1-Dimensional Cellular Automata: Reversibility and Semi-reversibility.

Reversibility of a one-dimensional finite cellular automaton (CA) is dependent on lattice size. A finite CA can be reversible for a set of lattice sizes. On the other hand, reversibility of an infinite CA, which is decided by exploring the rule only, is different in its kind from that of finite CA. Can we, however, link the reversibility of finite CA to that of infinite CA? In order to address this issue, we introduce a new notion, named semi-reversibility. We classify the CAs into three types with respect to reversibility property -- reversible, semi-reversible and strictly irreversible. A tool, reachability tree, has been used to decide the reversibility class of any CA. Finally, relation among the existing cases of reversibility is established.