  We show how to efficiently enumerate a class of finite-memory stochastic
processes using the causal representation of epsilon-machines. We characterize
epsilon-machines in the language of automata theory and adapt a recent
algorithm for generating accessible deterministic finite automata, pruning this
over-large class down to that of epsilon-machines. As an application, we
exactly enumerate topological epsilon-machines up to eight states and
six-letter alphabets.
