An automaton over data words that captures EMSO logic

TL;DR

This paper introduces class register automata, a new model for systems over infinite alphabets, and shows how they can be effectively derived from a logic for specifying such systems.

Contribution

It develops a unified automata and logic framework for infinite-alphabet systems, including a translation from logic to automata with elementary complexity.

Findings

Class register automata effectively model systems with infinite data values.

A logic for specifying such systems can be translated into automata in elementary time.

The framework captures communicating automata with unbounded processes.

Abstract

We develop a general framework for the specification and implementation of systems whose executions are words, or partial orders, over an infinite alphabet. As a model of an implementation, we introduce class register automata, a one-way automata model over words with multiple data values. Our model combines register automata and class memory automata. It has natural interpretations. In particular, it captures communicating automata with an unbounded number of processes, whose semantics can be described as a set of (dynamic) message sequence charts. On the specification side, we provide a local existential monadic second-order logic that does not impose any restriction on the number of variables. We study the realizability problem and show that every formula from that logic can be effectively, and in elementary time, translated into an equivalent class register automaton.