  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.
