Size (the number of states) of finite probabilistic automata with an isolated cut-point can be exponentially smaller than the size of any equivalent finite deterministic automaton. The result is presented in two versions. The first version depends on Artin’s Conjecture (1927) in Number Theory. The second version does not depend on conjectures but the numerical estimates are worse. In both versi...

Complementation and determinization are two fundamental notions in automata theory. The close relationship between the two has been well observed in the literature. In the case of nondeterministic finite automata on finite words (NFA), complementation and determinization have the same state complexity, namely Θ(2) where n is the state size. The same similarity between determinization and comple...

We address the problem of constructing hybrid translation systems by intersecting a Hiero-style hierarchical system with a phrase-based system and present formal techniques for doing so. We model the phrase-based component by introducing a variant of weighted finite-state automata, called σ-automata, provide a self-contained description of a general algorithm for intersecting weighted synchrono...

We continue the systematic investigation of probabilistic and quantum finite automata (PFAs and QFAs) on promise problems by focusing on unary languages. We show that bounded-error QFAs are more powerful than PFAs. But, in contrary to the binary problems, the computational powers of Las-Vegas QFAs and bounded-error PFAs are equivalent to deterministic finite automata (DFAs). Lastly, we present ...

This paper grew out of three tutorial lectures on automatic structures given at the Logic Colloquium 2007 in Wroc law (Poland). The paper will follow the outline of the tutorial lectures, supplementing some material along the way. We discuss variants of automatic structures related to several models of computation: word automata, tree automata, Büchi automata, and Rabin automata. Word automata ...

The simulation of deterministic pushdown automata defined over a one-letter alphabet by finite state automata is investigated from a descriptional complexity point of view. We show that each unary deterministic pushdown automaton of size s can be simulated by a deterministic finite automaton with a number of states that is exponential in s. We prove that this simulation is tight. Furthermore, i...

Dialogue managers are often based explicitly on finite state automata, but the present approach couples this type of dialogue manager with a semantic model (a city map) whose traversal is also formalised with a finite state automaton. The two automata are coupled in a scenario-specific fashion within an emergency rescue dialogue between an accident observer and an ambulance station, i.e. a stre...

We present some new results on realtime classical and quantum alternating models. Firstly, we show that the emptiness problem for alternating one-counter automata on unary alphabets is undecidable. Then, we define realtime private alternating finite automata (PAFAs) and show that they can recognize some non-regular unary languages, and the emptiness problem is undecidable for them. Moreover, PA...

Abstract We present algorithms for model checking and controller synthesis of timed automata, seeing a automaton as parallel composition large finite-state machine relatively smaller automaton, using compositional reasoning on this composition. use automata learning to learn finite approximations the component, in order reduce problem at hand or synthesis. an experimental evaluation our approach.

Watson–Crick automata are finite state automata working on double-stranded tapes, introduced to investigate the potential of DNA molecules for computing. In this paper, we continue the investigation of descriptional complexity ofWatson–Crick automata initiated by Păun et al. [A. Păun, M. Păun, State and transition complexity of Watson–Crick finite automata, in: G. Ciobanu, G. Paun (Eds.), Funda...