History-deterministic Parikh Automata

Enzo Erlich , Shibashis Guha , Ismaël Jecker , Karoliina Lehtinen (1) , Martin Zimmermann

1 MOVE - Modélisation et Vérification

Parikh automata extend finite automata by counters that can be tested for membership in a semilinear set, but only at the end of a run. Thereby, they preserve many of the desirable properties of finite automata. Deterministic Parikh automata are strictly weaker than nondeterministic ones, but enjoy better closure and algorithmic properties. This state of affairs motivates the study of intermediate forms of nondeterminism. Here, we investigate history-deterministic Parikh automata, i.e., automata whose nondeterminism can be resolved on the fly. This restricted form of nondeterminism is well-suited for applications which classically call for determinism, e.g., solving games and composition. We show that history-deterministic Parikh automata are strictly more expressive than deterministic ones, incomparable to unambiguous ones, and enjoy almost all of the closure properties of deterministic automata.

Keywords: Parikh automata; History-determinism; Reversal-bounded Counter Machines; Theory of computation → Formal languages and automata theory

Domains: Computer Science [cs]

Enzo Erlich, Shibashis Guha, Ismaël Jecker, Karoliina Lehtinen, Martin Zimmermann. History-deterministic Parikh Automata. 34th International Conference on Concurrency Theory, Sep 2023, Antwerp, Belgium. ⟨10.4230/LIPIcs.CONCUR.2023.31⟩. ⟨hal-04222543⟩