Abstract
Two transformations are presented which, for any pushdown automaton (PDA)M withn states andp stack symbols, reduce the number of stack symbols to any desired numberp′ greater than one. The first transformation preserves deterministic behavior and produces an equivalent PDA witho(np/p′) states. The second construction, using a technique which introduces nondeterminism, produces an equivalent PDA withO(n√p/p′) states. Both transformations are essentially optimal, the former among determinism-preserving transformations, the latter among all transformations.
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References
J. Goldstine, C. M. R. Kintala, and D. Wotschke. On measuring nondeterminism in regular languages.Information and Computation, 86:179–194, 1990.
J. Goldstine, J. K. Price, and D. Wotschke. On reducing the number of states in a pda.Mathematical Systems Theory, 15:315–321, 1982.
J. Goldstine, J. K. Price, and D. Wotschke. A pushdown automaton or a context-free grammar—which is more economical?Theoretical Computer Science, 18:33–40, 1982.
S. Greibach. An infinite hierarchy of context-free languages.Journal of the ACM, 14:91–106, 1966.
J. Hartmanis.On the Succinctness of Different Representations of Languages. Lecture Notes in Computer Science, vol. 71. Springer-Verlag, Berlin, pp. 282–288, 1979.
J. Hartmanis. On Gödel speed-up and succinctness of language representations.Theoretical Computer Science, 26:335–342, 1983.
C. M. R. Kintala and D. Wotschke. Amount of nondeterminism in finite automata.Acta Informatica, 13:199–204, 1980.
A. R. Meyer and M. J. Fischer. Economy of description by automata, grammars, and formal systems.Proc. 12th Symposium on Switching and Automata Theory, pp. 188–191, 1981.
E. M. Schmidt and T. G. Szymanski. Succinctness of descriptions of unambiguous context-free languages.SIAM Journal on Computing, 6:547–553, 1977.
R. E. Stearns. A regularity test for pushdown machines.Information and Control, 11:323–340, 1967.
L. G. Valiant. Regularity and related problems for deterministic pushdown automata.Journal of the ACM, 22:1–10, 1975.
L. G. Valiant. A note on the succinctness of descriptions of deterministic languages.Information and Control, 32:139–145, 1976.
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This research was supported in part by the National Science Foundation under Grants MCS 76-10076 and MCS 76-10076A01 and by the Stiftung Volkswagenwerk under Grant No. II/62 325.
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Goldstine, J., Price, J.K. & Wotschke, D. On reducing the number of stack symbols in a PDA. Math. Systems Theory 26, 313–326 (1993). https://doi.org/10.1007/BF01189852
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DOI: https://doi.org/10.1007/BF01189852