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Binary patterns in binary cube-free words: Avoidability and growth∗

Published online by Cambridge University Press:  17 July 2014

Robert Mercaş ,
Pascal Ochem ,
Alexey V. Samsonov  and
Arseny M. Shur
Robert Mercaş
Affiliation:
Christian-Albrechts-Universität zu Kiel, Institut für Informatik, Germany.. [email protected]
Pascal Ochem
Affiliation:
CNRS, LIRMM, France.; [email protected]
Alexey V. Samsonov
Affiliation:
Ural Federal University, Ekaterinburg, Russia.; [email protected] ; [email protected] ;
Arseny M. Shur
Affiliation:
Ural Federal University, Ekaterinburg, Russia.; [email protected] ; [email protected] ;
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Abstract

The avoidability of binary patterns by binary cube-free words is investigated and the exact bound between unavoidable and avoidable patterns is found. All avoidable patterns are shown to be D0L-avoidable. For avoidable patterns, the growth rates of the avoiding languages are studied. All such languages, except for the overlap-free language, are proved to have exponential growth. The exact growth rates of languages avoiding minimal avoidable patterns are approximated through computer-assisted upper bounds. Finally, a new example of a pattern-avoiding language of polynomial growth is given.

Keywords

Formal languagesavoidabilityavoidable patterncube-free wordoverlap-free wordgrowth ratemorphism
Type
Research Article
Information
RAIRO - Theoretical Informatics and Applications , Volume 48 , Issue 4: Special issue in the honor of the 14th "Journées Montoises d'Informatique Théorique" , October 2014 , pp. 369 - 389
Copyright
© EDP Sciences 2014

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