Chapter 3: The World of Simple Programs

Section 10: Symbolic Systems

Network analogs [of symbolic systems]

The state of a symbolic system can always be viewed as corresponding to a tree. If a more general network is allowed then rules based on analogs of network substitution systems from page 508 can be used. (One can also construct an infinite tree from a general network by following all its possible paths, as on page 277, but in most cases there will be no simple way to apply symbolic system rules to such a tree.)

From Stephen Wolfram: A New Kind of Science [citation]