  AND-OR networks are Boolean networks where each coordinate function is either
the AND or OR logical operator. We study the number of fixed points of these
Boolean networks in the case that they have a wiring diagram with chain
topology. We find closed formulas for subclasses of these networks and
recursive formulas in the general case. Our results allow for an effective
computation of the number of fixed points in the case that the topology of the
Boolean network is an open chain (finite or infinite) or a closed chain.
