skip to main content
article

Complementing two-way finite automata

Published: 01 August 2007 Publication History

Abstract

We study the relationship between the sizes of two-way finite automata accepting a language and its complement. In the deterministic case, for a given automaton (2dfa) with n states, we build an automaton accepting the complement with at most 4n states, independently of the size of the input alphabet. Actually, we show a stronger result, by presenting an equivalent 4n-state 2dfa that always halts. For the nondeterministic case, using a variant of inductive counting, we show that the complement of a unary language, accepted by an n-state two-way automaton (2nfa), can be accepted by an O(n^8)-state 2nfa. Here we also make 2nfa's halting. This allows the simulation of unary 2nfa's by probabilistic Las Vegas two-way automata with O(n^8) states.

References

[1]
P. Berman, A. Lingas, On the complexity of regular languages in terms of finite automata. Tech. Report 304, Polish Academy of Sciences, 1977.
[2]
Dietzelfelbinger, M., Kutylowski, M. and Reischuk, R., Exact lower bounds for computing Boolean functions on CREW PRAMs. J. Comput. Syst. Sci. v48. 231-254.
[3]
Geffert, V., Tally versions of the Savitch and Immerman--Szelepcsényi theorems for sublogarithmic space. SIAM J. Comput. v22. 102-113.
[4]
Geffert, V., Mereghetti, C. and Pighizzini, G., Converting two-way nondeterministic automata into simpler automata. Theoret. Comput. Sci. v295. 189-203.
[5]
Goldstine, J., Kappes, M., Kintala, C., Leung, H., Malcher, A. and Wotschke, D., Descriptional complexity of machines with limited resources. J. Universal Comput. Sci. v8. 193-234.
[6]
Hopcroft, J. and Ullman, J., Introduction to Automata Theory, Languages, and Computation. 1979. Addison-Wesley, Reading, MA.
[7]
Hromkovič, J. and Schnitger, G., On the power of Las Vegas II: two-way finite automata. Theoret. Comput. Sci. v262. 1-24.
[8]
Hromkovič, J. and Schnitger, G., On the power of Las Vegas for one-way communication complexity, OBDDs, and finite automata. Inform. Comput. v169. 284-296.
[9]
Immerman, N., Nondeterministic space is closed under complementation. SIAM J. Comput. v17. 935-938.
[10]
Jirásek, J., Jirásková, G. and Szabari, A., State complexity of concatenation and complementation. Int. J. Found. Comput. Sci. v16. 511-529.
[11]
C. Kapoutsis, Deterministic moles cannot solve liveness, in: Proc. 7th Int. Workshop on Descriptional Complexity of Formal Systems (DCFS 2005), University of St. Milano, Como, Italy, 2005, pp. 194--205.
[12]
A. Kondacs, J. Watrous, On the power of quantum finite state automata, in: Proc. 38th Symp. Found. Comp. Sci. (FOCS 1997), IEEE Computer Society Press, 1997, pp. 66--75.
[13]
Mera, F. and Pighizzini, G., Complementing unary nondeterministic automata. Theoret. Comput. Sci. v330. 349-360.
[14]
Mereghetti, C. and Pighizzini, G., Two-way automata simulations and unary languages. J. Aut. Lang. Combin. v5. 287-300.
[15]
A. Meyer, M. Fischer, Economy of description by automata, grammars, and formal systems, in: Proc. 12th Ann. IEEE Symp. on Switching and Automata Theory, 1971, pp. 188--191.
[16]
Moore, C. and Crutchfield, J., Quantum automata and quantum grammars. Theoret. Comput. Sci. v237. 275-306.
[17]
Moore, F., On the bounds for state-set size in the proofs of equivalence between deterministic, nondeterministic and two-way finite automata by deterministic automata. IEEE Trans. Comput. vC-20. 1211-1219.
[18]
Rabin, M.O., Probabilistic automata. Inform. Control. v6. 230-245.
[19]
W. Sakoda, M. Sipser, Nondeterminism and the size of two-way finite automata, in: Proc. 10th ACM Symp. Theory of Computing, 1978, pp. 275--286.
[20]
Sipser, M., Lower bounds on the size of sweeping automata. J. Comput. Syst. Sci. v21. 195-202.
[21]
Sipser, M., Halting space bounded computations. Theoret. Comput. Sci. v10. 335-338.
[22]
Szelepcsényi, R., The method of forced enumeration for nondeterministic automata. Acta Inform. v26. 279-284.
[23]
Vardi, M.Y., A note on the reduction of two-way automata to one-way automata. Inform. Process. Lett. v30. 261-264.

Cited By

View all

Recommendations

Comments

Please enable JavaScript to view thecomments powered by Disqus.

Information & Contributors

Information

Published In

cover image Information and Computation
Information and Computation  Volume 205, Issue 8
August, 2007
179 pages

Publisher

Academic Press, Inc.

United States

Publication History

Published: 01 August 2007

Author Tags

  1. Descriptional complexity
  2. Finite state automata
  3. Formal languages

Qualifiers

  • Article

Contributors

Other Metrics

Bibliometrics & Citations

Bibliometrics

Article Metrics

  • Downloads (Last 12 months)0
  • Downloads (Last 6 weeks)0
Reflects downloads up to 01 Nov 2024

Other Metrics

Citations

Cited By

View all

View Options

View options

Get Access

Login options

Media

Figures

Other

Tables

Share

Share

Share this Publication link

Share on social media