Right (left, two-sided) extendable part of a language consists of all words having infinitely many right (resp. left, two-sided) extensions within the language. We prove that for an arbitrary factorial language each of these parts has the same growth rate of complexity as the language itself. On the other hand, we exhibit a factorial language which grows superpolynomially, while its two-sided extendable part grows only linearly.
@article{ITA_2008__42_3_647_0, author = {Shur, Arseny M.}, title = {Comparing complexity functions of a language and its extendable part}, journal = {RAIRO - Theoretical Informatics and Applications - Informatique Th\'eorique et Applications}, volume = {42}, year = {2008}, pages = {647-655}, doi = {10.1051/ita:2008021}, mrnumber = {2434040}, zbl = {1149.68055}, language = {en}, url = {http://dml.mathdoc.fr/item/ITA_2008__42_3_647_0} }
Shur, Arseny M. Comparing complexity functions of a language and its extendable part. RAIRO - Theoretical Informatics and Applications - Informatique Théorique et Applications, Tome 42 (2008) pp. 647-655. doi : 10.1051/ita:2008021. http://gdmltest.u-ga.fr/item/ITA_2008__42_3_647_0/
[1] Combinatorics of words, in Handbook of formal languages 1, edited by G. Rosenberg, A. Salomaa. Springer, Berlin (1997) 329-438. | MR 1469998
and ,[2] Spectra of graphs. Theory and applications, 3rd edn. Johann Ambrosius Barth, Heidelberg (1995). | MR 1324340 | Zbl 0824.05046
, and ,[3] On the structure of counting function of sparse context-free languages. Theor. Comput. Sci. 356 (2006) 104-117. | MR 2217830 | Zbl 1160.68407
, and ,[4] A limit theorem for sets of subwords in deterministic TOL languages. Inform. Process. Lett. 2 (1973) 70-73. | MR 323162 | Zbl 0299.68044
and ,[5] Application of the theory of matrices. Interscience, New York (1959). | MR 107648 | Zbl 0085.01001
,[6] On sparseness, ambiguity and other decision problems for acceptors and transducers. Lect. Notes Comput. Sci. 210 (1986) 171-179. | MR 827734 | Zbl 0605.68080
and ,[7] Repetition-free words. Theor. Comput. Sci. 44 (1986) 175-197. | MR 860554 | Zbl 0596.20058
,[8] Enumeration of irreducible binary words. Discrete Appl. Math. 20 (1988) 221-232. | MR 944122 | Zbl 0673.68046
,[9] A characterization of -free words over a binary alphabet. Turku Centre for Computer Science, TUCS Tech. Report 74 (1996).
,[10] Symbolic dynamics. Amer. J. Math. 60 (1938) 815-866. | JFM 64.0798.04 | MR 1507944
and ,[11] Combinatorial complexity of rational languages. Discrete Anal. Oper. Res. 1 12 (2005) 78-99 (Russian). | MR 2168157
,[12] On intermediate factorial languages. Turku Centre for Computer Science, TUCS Tech. Report 723 (2005). | MR 2168157
,