Abstract
Hardness of a separation of nondeterminism, randomization and determinism for polynomial time computations has motivated the analysis of this issue for restricted models of computation. Following this line of research, we consider randomized length-reducing two-pushdown automata ( \(\mathsf{lrTPDA}\) ), a natural extension of pushdown automata ( \(\mathsf{PDA}\) ). Our main results are as follows. We show that deterministic \(\mathsf{lrTPDA}\) s are weaker than Las Vegas \(\mathsf{lrTPDA}\) s which in turn are weaker than Monte Carlo \(\mathsf{lrTPDA}\) s. Moreover, bounded two-sided error \(\mathsf{lrTPDA}\) s are stronger than Monte Carlo \(\mathsf{lrTPDA}\) s and they are able to recognize some languages which cannot be recognized nondeterministically. Finally, we prove that amplification is impossible for Las Vegas and Monte Carlo automata.
Similar content being viewed by others
References
Buntrock, G., Loryś, K.: On growing context-sensitive languages. In: ICALP. Lecture Notes in Computer Science, vol. 623, pp. 77–88. Springer, Berlin (1992)
Buntrock, G., Otto, F.: Growing context-sensitive languages and Church–Rosser languages. Inf. Comput. 141(1), 1–36 (1998)
Ďuriš, P., Hromkovič, J., Rolim, J.D.P., Schnitger, G.: Las Vegas versus determinism for one-way communication complexity, finite automata, and polynomial-time computations. In: STACS. Lecture Notes in Computer Science, vol. 1200, pp. 117–128. Springer, Berlin (1997)
Hromkovič, J., Schnitger, G.: On the power of randomized pushdown automata. In: Developments in Language Theory (DLT). Lecture Notes in Computer Science, vol. 2295, pp. 262–271. Springer, Berlin (2001)
Hromkovič, J., Schnitger, G.: Pushdown automata and multicounter machines, a comparison of computation modes. In: ICALP. Lecture Notes in Computer Science, vol. 2719, pp. 66–80. Springer, Berlin (2003)
Hromkovič, J., Schnitger, G.: On the power of Las Vegas II: two-way finite automata. Theor. Comput. Sci. 262(1), 1–24 (2001)
Dahlhaus, E., Warmuth, M.K.: Membership for growing context-sensitive grammars is polynomial. J. Comput. Syst. Sci. 33(3), 456–472 (1986)
Jurdziński, T., Loryś, K.: Lower bound technique for length-reducing automata. Inf. Comput. 205(9), 387–1412 (2007)
Jurdziński, T.: Probabilistic length-reducing automata. In: MFCS. Lecture Notes in Computer Science, vol. 4162, pp. 561–572. Springer, Berlin (2006)
Kaneps, J., Geidmanis, D., Freivalds, R.: Tally languages accepted by Monte Carlo pushdown automata. In: RANDOM. Lecture Notes in Computer Science, vol. 1269, pp. 187–195. Springer, Berlin (1997)
Li, M., Vitanyi, P.: An Introduction to Kolmogorov Complexity and its Applications. Springer, Berlin (1993)
Macarie, I.I., Ogihara, M.: Properties of probabilistic pushdown automata. Theor. Comput. Sci. 207(1), 117–130 (1998)
McNaughton, R.: An insertion into the Chomsky hierarchy? In: Karhumaki, J., Maurer, H.A., Paun, G., Rozenberg, G. (eds.) Jewels are Forever, Contributions on TCS in Honour of A. Salomaa, pp. 204–212. Springer, Berlin (1999)
McNaughton, R., Narendran, P., Otto, F.: Church–Rosser Thue systems and formal languages. J. Assoc. Comput. Mach. 35, 324–344 (1988)
Niemann, G.: Church–Rosser languages and related classes. PhD thesis. Univ. Kassel (2002)
Niemann, G., Otto, F.: The Church–Rosser languages are the deterministic variants of the growing context-sensitive languages. Inf. Comput. 197(1–2), 1–21 (2005)
Sauerhoff, M.: Randomness versus nondeterminism for read-once and read-k branching programs. In: STACS 03. Lecture Notes in Computer Science, vol. 2607, pp. 307–318. Springer, Berlin (2003)
Author information
Authors and Affiliations
Corresponding author
Additional information
Partially supported by MNiSW grant number N206 024 31/3826, 2006-2008. An extended abstract of this paper appeared in the MFCS06 Proceedings (Lecture Notes in Computer Science, vol. 4162, pp. 561–572, 2006).
Rights and permissions
About this article
Cite this article
Jurdziński, T. Probabilistic Length-Reducing Two-Pushdown Automata. Theory Comput Syst 45, 74–107 (2009). https://doi.org/10.1007/s00224-007-9066-x
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00224-007-9066-x