The Generalization of Generalized Automata: Expression Automata

We explore expression automata with respect to determinism, minimization and primeness. We define determinism of expression automata using prefix-freeness. This approach is, to some extent, similar to that of Giammarresi and Montalbano’s definition of deterministic generalized automata. We prove that deterministic expression automata languages are a proper subfamily of the regular languages. We define the minimization of deterministic expression automata. Lastly, we discuss prime prefix-free regular languages. Note that we have omitted almost all proofs in this preliminary version.