Subwords and power-free words are not expressible by word equations

• Autorzy: Ilie L.
• Języki publikacji: EN

Abstrakty

EN

We consider several open problems of Karhumäki, Mignosi and Plandowski, cf. [KMP], con-cerning the expressibility of languages and relations as solutions of word equations. We show first that the (scattered) subword relation is not expressible. Then, we consider the set of k-power-free finite words and solve it negatively for all nontrivial integer values of k. Finally, we consider the Fibonacci finite words. We do not solve the problem of the expressibility of the set of these words but prove that a negative answer (as believed) cannot be given using the tools in [KMP].

Słowa kluczowe

EN

word equation; subword; power-free; Fibonacci

• Wydawca: IOS Press
• Czasopismo: Fundamenta Informaticae
• Rocznik: 1999
• Tom: Vol. 38, Nr 1,2
• Strony: 109--118
• Opis fizyczny: bibliogr. 15 poz.

Twórcy

autor

Ilie L.

• Turku Centre for Computer Science TUCS, FIN-20520 Turku, Finland,