This is a reissue of the book Tree Automata by F. G\'ecseg and M. Steinby originally published in 1984 by Akad\'emiai Kiad\'o, Budapest. Some mistakes have been corrected and a few obscure passages have been clarified. Moreover, some more recent contributions and current lines of research are reviewed in an appendix that also contains several new references.
In this paper we give a structural characterization of three classes of tree au-tomata. Namely, we shall homomorphically represent the classes of nilpotent, definite, and monotone tree automata by means of quasi-cascade-products of unary nilpotent and unary definite tree automata in the first two cases, and by means of products of simpler tree automata in… (More)