Displaying similar documents to “Free group languages: Rational versus recognizable”

Free group languages : rational versus recognizable

Pedro V. Silva (2004)

RAIRO - Theoretical Informatics and Applications - Informatique Théorique et Applications

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We provide alternative proofs and algorithms for results proved by Sénizergues on rational and recognizable free group languages. We consider two different approaches to the basic problem of deciding recognizability for rational free group languages following two fully independent paths: the symmetrification method (using techniques inspired by the study of inverse automata and inverse monoids) and the right stabilizer method (a general approach generalizable to other classes of groups)....

Decision problems among the main subfamilies of rational relations

Olivier Carton, Christian Choffrut, Serge Grigorieff (2006)

RAIRO - Theoretical Informatics and Applications

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We consider the four families of recognizable, synchronous, deterministic rational and rational subsets of a direct product of free monoids. They form a strict hierarchy and we investigate the following decision problem: given a relation in one of the families, does it belong to a smaller family? We settle the problem entirely when all monoids have a unique generator and fill some gaps in the general case. In particular, adapting a proof of Stearns, we show that it is recursively decidable whether...

On the continuity set of an Omega rational function

Olivier Carton, Olivier Finkel, Pierre Simonnet (2008)

RAIRO - Theoretical Informatics and Applications

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In this paper, we study the continuity of rational functions realized by Büchi finite state transducers. It has been shown by Prieur that it can be decided whether such a function is continuous. We prove here that surprisingly, it cannot be decided whether such a function  has at least one point of continuity and that its continuity set cannot be computed. In the case of a synchronous rational function, we show that its continuity set is rational and that it can be computed....

Closure under union and composition of iterated rational transductions

D. Simplot, A. Terlutte (2010)

RAIRO - Theoretical Informatics and Applications

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We proceed our work on iterated transductions by studying the closure under union and composition of some classes of iterated functions. We analyze this closure for the classes of length-preserving rational functions, length-preserving subsequential functions and length-preserving sequential functions with terminal states. All the classes we obtain are equal. We also study the connection with deterministic context-sensitive languages.