Displaying similar documents to “Axiomatizing omega and omega-op powers of words”

Theories of orders on the set of words

Dietrich Kuske (2006)

RAIRO - Theoretical Informatics and Applications - Informatique Théorique et Applications

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It is shown that small fragments of the first-order theory of the subword order, the (partial) lexicographic path ordering on words, the homomorphism preorder, and the infix order are undecidable. This is in contrast to the decidability of the monadic second-order theory of the prefix order [M.O. Rabin, Trans. Amer. Math. Soc., 1969] and of the theory of the total lexicographic path ordering [P. Narendran and M. Rusinowitch, Lect. Notes Artificial Intelligence, 2000] and, in case of...

On the simplest centralizer of a language

Paolo Massazza, Petri Salmela (2006)

RAIRO - Theoretical Informatics and Applications

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Given a finite alphabet and a language , the centralizer of is defined as the maximal language commuting with it. We prove that if the primitive root of the smallest word of (with respect to a lexicographic order) is prefix distinguishable in then the centralizer of is as simple as possible, that is, the submonoid . This lets us obtain a simple proof of a known result concerning the centralizer of nonperiodic three-word languages.

Sturmian jungle (or garden?) on multiliteral alphabets

L'ubomíra Balková, Edita Pelantová, Štěpán Starosta (2010)

RAIRO - Theoretical Informatics and Applications - Informatique Théorique et Applications

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The properties characterizing sturmian words are considered for words on multiliteral alphabets. We summarize various generalizations of sturmian words to multiliteral alphabets and enlarge the list of known relationships among these generalizations. We provide a new equivalent definition of rich words and make use of it in the study of generalizations of sturmian words based on palindromes. We also collect many examples of infinite words to illustrate differences in the generalized...

Asymptotic behaviour of bi-infinite words

Wit Foryś (2004)

RAIRO - Theoretical Informatics and Applications - Informatique Théorique et Applications

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We present a description of asymptotic behaviour of languages of bi-infinite words obtained by iterating morphisms defined on free monoids.

A Hierarchy of Automatic -Words having a Decidable MSO Theory

Vince Bárány (2008)

RAIRO - Theoretical Informatics and Applications

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We investigate automatic presentations of -words. Starting points of our study are the works of Rigo and Maes, Caucal, and Carton and Thomas concerning lexicographic presentation, MSO-interpretability in algebraic trees, and the decidability of the MSO theory of morphic words. Refining their techniques we observe that the lexicographic presentation of a (morphic) word is in a certain sense canonical. We then generalize our techniques to a hierarchy of classes of -words enjoying...

Directive words of episturmian words : equivalences and normalization

Amy Glen, Florence Levé, Gwénaël Richomme (2009)

RAIRO - Theoretical Informatics and Applications - Informatique Théorique et Applications

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Episturmian morphisms constitute a powerful tool to study episturmian words. Indeed, any episturmian word can be infinitely decomposed over the set of pure episturmian morphisms. Thus, an episturmian word can be defined by one of its morphic decompositions or, equivalently, by a certain directive word. Here we characterize pairs of words directing the same episturmian word. We also propose a way to uniquely define any episturmian word through a normalization of its directive words. As...