Abstract
We prove the following two variants of the defect theorem. Let X be a finite set of words over a finite alphabet. Then if a nonperiodic bi-infinite word w has two X-factorizations, then the combinatorial rank of X is at most card(X) - 1, i.e. there exists a set F such that \(X \subseteq F^ + \) with card(F) < card(X). Further, if card(X)=2 and a bi-infinite word possesses two X-factorizations which are not shift-equivalent, then the primitive roots of the words in X are conjugates. Moreover, in the case card(F)=card(X), the number of periodic bi-infinite words which have two different X-factorizations is finite and in the two-element case there is at most one such bi-infinite word.
Supported by Academy of Finland under Grant No. 14047.
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References
Choffrut, C., Karhumäki, J., Combinatorics of words, in G. Rozenberg and A. Salomaa (eds), Handbook of Formal Languages, Springer, 1997.
Le Rest, E., Le Rest, M. Sur la combinatoire des codes a deux mots, Theoretical Computer Science 41, 61–80, 1985.
Lothaire, M., Combinatorics on words, Addison-Wesley, 1983.
Harju, T., Karhumäki, J., On the defect theorem and simplifiability, Semigroup Forum 33, 199–217, 1986.
Lentin, A., Schützenberger, M.P., A combinatorial problem in the theory of free monoids, Proc. University of North Carolina, 128–144, 1967.
Lyndon, R.C., Schützenberger, M. P., The equation a m = b n c p in a free group, Michigan Mathematical Journal 9, 289–298, 1962.
Karhumäki, J., Maňuch, J., Plandowski, W., On defect effect of bi-infinite words, TUCS Report 181, 1998.
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Karhumäki, J., Maňuch, J., Plandowski, W. (1998). On defect effect of bi-infinite words. In: Brim, L., Gruska, J., Zlatuška, J. (eds) Mathematical Foundations of Computer Science 1998. MFCS 1998. Lecture Notes in Computer Science, vol 1450. Springer, Berlin, Heidelberg. https://doi.org/10.1007/BFb0055818
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DOI: https://doi.org/10.1007/BFb0055818
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