The main results of the paper concern graphs of linear cellular automata wi
th boundary conditions. We show that the connected components of such graph
s are direct sums of trees and cycles, and we provide a complete characteri
zation of the trees, as well as enumerate the cycles of various lengths. Ou
r work generalizes and clarifies results obtained previously in special cas
es. (C) 2001 Published by Elsevier Science Inc. All rights reserved.