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Unambiguous recognizable two-dimensional languages

Published online by Cambridge University Press:  20 July 2006

Marcella Anselmo
Affiliation:
Dipartimento di Informatica ed Applicazioni, Università di Salerno, 84081 Baronissi, (Salerno), Italy; anselmo@dia.unisa.it
Dora Giammarresi
Affiliation:
Dipartimento di Matematica, Università di Roma “Tor Vergata”, via Ricerca Scientifica, 00133 Roma, Italy; giammarr@mat.uniroma2.it
Maria Madonia
Affiliation:
Dipartimento di Matematica e Informatica, Università di Catania, Viale Andrea Doria 6/a, 95125 Catania, Italy; madonia@dmi.unict.it
Antonio Restivo
Affiliation:
Dipartimento di Matematica e Applicazioni, Università di Palermo, via Archirafi 34, 90123 Palermo, Italy; restivo@dipmat.math.unipa.it
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Abstract

We consider the family UREC of unambiguous recognizable two-dimensional languages. We prove that there are recognizable languages that are inherently ambiguous, that is UREC family is a proper subclass of REC family. The result is obtained by showing a necessary condition for unambiguous recognizable languages. Further UREC family coincides with the class of picture languages defined by unambiguous 2OTA and it strictly contains its deterministic counterpart. Some closure and non-closure properties of UREC are presented. Finally we show that it is undecidable whether a given tiling system is unambiguous.

Type
Research Article
Copyright
© EDP Sciences, 2006

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References

Anselmo, M., Giammarresi, D. and Madonia, M., New Operations and Regular Expressions for two-dimensional languages over one-letter alphabet. Theoret. Comput. Sci. 340 (2005) 408431. CrossRef
J. Berstel and D. Perrin, Theory of Codes. Academic Press (1985).
A. Bertoni, G. Mauri and N. Sabadini, Unambiguous regular trace languages, in Algebra, Combinatorics and Logic in Computer Science, edited by J. Demetrovics, G. Katona and A. Salomaa, North Holland. Math. Soc. Janos Bolyay 42 (1985).
S. Bozapalidis and A. Grammatikopoulou, Recognizable picture series, in Special Issue on Weighted Automata. Journal of Automata, Languages and Combinatorics, Vol. 10, No. 2 (2005).
M. Blum and C. Hewitt, Automata on a two-dimensional tape, in IEEE Symposium on Switching and Automata Theory (1967) 155–160.
Choffrut, C. and Durak, B., Collage of two-dimensional words. Theoret. Comput. Sci. 340 (2005) 364380. CrossRef
M. Chrobak and W. Rytter, Unique decipherability for partially commutative alphabets. Fundamenta Informatica X (1987) 323–336.
Crespi Reghizzi, S. and Pradella, M., Tile rewriting grammars and picture languages. Theoret. Comput. Sci. 340 (2005) 257272. CrossRef
S. Eilenberg, Automata, Languages and Machines. Vol. A, Academic Press (1974).
Giammarresi, D. and Restivo, A., Recognizable picture languages. International Journal Pattern Recognition and Artificial Intelligence 6 (1992) 241256. CrossRef
D. Giammarresi and A. Restivo, Two-dimensional languages, in Handbook of Formal Languages, edited by G. Rozenberg and A. Salomaa. Springer-Verlag, Berlin III (1997) 215–268.
Giammarresi, D., Restivo, A., Seibert, S. and Thomas, W., Monadic second order logic over pictures and recognizability by tiling systems. Inform. Computat. 125 (1996) 3245. CrossRef
Hromkovic, J., Karumäki, J., Klauck, H., Schnitger, G. and Seibert, S., Communication Complexity Method for Measuring Nondeterminism in Finite Automata. Inform. Comput. 172 (2002) 202217. CrossRef
Inoue, K. and Nakamura, A., Some properties of two-dimensional on-line tessellation acceptors. Information Sciences 13 (1977) 95121. CrossRef
Inoue, K. and Nakamura, A., Nonclosure properties of two-dimensional on-line tessellation acceptors and one-way parallel/sequential array acceptors. Trans. IECE Japan 6 (1977) 475476.
K. Inoue and I. Takanami, A Characterization of recognizable picture languages, in Proc. Second International Colloquium on Parallel Image Processing, edited by A. Nakamura et al. Lect. Notes Comput. Sci. 654 (1993).
J. Kari and C. Moore, Rectangles and squares recognized by two-dimensional automata, in Theory is Forever, edited by Karhumaki et al. Lect. Notes Comput. Sci. 3113 (2004) 134–144.
O. Matz, On piecewise testable, starfree, and recognizable picture languages, in Foundations of Software Science and Computation Structures, edited by M. Nivat, Springer-Verlag, Berlin 1378 (1998).
O. Matz and W. Thomas, The Monadic Quantifier Alternation Hierarchy over Graphs is Infinite, in IEEE Symposium on Logic in Computer Science, LICS. IEEE (1997) 236–244.
I. Mäurer, Recognizable and Rational Picture Series, in Procs. Conf. on Algebraic Informatics, Thessaloniki (2005), Aristotte University of Thessaloniki.
Mäurer, I., Weighted Picture Automata and Weighted Logics, in Procs. STACS 2006, Springer Belin. Lect. Notes Comput. Sci. 3884 (2006) 313324. CrossRef
Potthoff, A., Seibert, S. and Thomas, W., Nondeterminism versus determinism of finite automata over directed acyclic graphs. Bulletin Belgian Math. Soc. 1 (1994) 285298.
J. Sakarovitch, Eléments de théorie des automates. Vuibert, Paris (2003).
Thomas, W., Logics, On, Tilings, and Automata, in Proc. 18th ICALP, Springer-Verlag, Berlin. Lect. Notes Comput. Sci. 510 (1991) 441453. CrossRef