ω-automaton

About: ω-automaton is a research topic. Over the lifetime, 2299 publications have been published within this topic receiving 68468 citations. The topic is also known as: stream automaton & ω-automata.

A succinct canonical register automaton model

Abstract: We present a novel canonical automaton model, based on register automata, that can be used to specify protocol or program behavior. Register automata have a finite control structure and a finite number of registers (variables), and process sequences of terms that carry data values from an infinite domain. We consider register automata that compare data values for equality. A major contribution is the definition of a canonical automaton representation of any language recognizable by a deterministic register automaton, by means of a Nerode congruence. This canonical form is well suited for modeling, e.g., protocols or program behavior. Our model can be exponentially more succinct than previous proposals, since it filters out ‘accidental’ relations between data values. This opens the way to new practical applications, e.g., in automata learning.

On stateless two-pushdown automata and restarting automata

Abstract: Restarting automata and two-pushdown automata are investigated that have a single internal state only. As such an automaton must always stay in the same state, this state is of no importance for the behaviour of the automaton. Accordingly, these automata are called stateless. We consider various types of stateless two-pushdown automata and restarting automata. We investigate their expressive power, comparing them in particular to each other and to the corresponding types of automata with states.

On finite automata with a time-variant structure

Abstract: Basic theory of finite automata whose state transitions and outputs depend on time is developed. A necessary and sufficient condition for a language to be accepted by such an automaton is established. Interrelations between various types of time-variant automata, including nondeterministic ones, are studied. Results concerning the closure (under various operations) of the family of languages accepted by time-variant automata are obtained. Finally, time-variant automata are compared with other types of automata.

A lower bound for the length of the shortest carefully synchronizing words

Abstract: We introduce the notion of careful synchronization for partial finite automata as a natural generalization of the synchronization notion for complete finite automata We obtain a lower bound for the careful synchronization threshold for automata with a given number of states

Complexity of problems concerning carefully synchronizing words for PFA and directing words for NFA

Abstract: We show that the problem of checking careful synchronizability of partial finite automata and the problem of finding the shortest carefully synchronizing word are PSPACE-complete. We show that the problem of checking D1, D2 and D3-directability of nondeterministic finite automata and the problem of finding the shortest D1, D2 and D3-directing word are PSPACE-complete. The restrictions of these problems to 2-letter automata remain PSPACE-complete.