Abstract
Among the many models of language acceptors that have been studied in the literature are multihead finite automata (finite automata with multiple one-way input heads) and 1-reversal counter machines (finite automata with multiple counters, where each counter can only “reverse” once, i.e., once a counter decrements, it can no longer increment). The devices can be deterministic or nondeterministic and can be augmented with a pushdown stack. We investigate the relative computational power of these machines. Our results (where C 1 and C 2 are classes of machines) are of the following types:
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1
Machines in C 1 and C 2 are incomparable.
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2
Machines in C 1 are strictly weaker than machines in C 2.
In obtaining results of these types, we use counting and “cut-and-paste” arguments as well as an interesting technique that shows that if a language were accepted by a device in a given class, then all recursively enumerable languages would be decidable.
This research was supported by the National Science Foundation Grant CCF-0524136 of Oscar H. Ibarra, and by Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant R2824A01, the Canada Research Chair Award in Biocomputing to Lila Kari.
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Chiniforooshan, E., Daley, M., Ibarra, O.H., Kari, L., Seki, S. (2011). One-Reversal Counter Machines and Multihead Automata: Revisited. In: Černá, I., et al. SOFSEM 2011: Theory and Practice of Computer Science. SOFSEM 2011. Lecture Notes in Computer Science, vol 6543. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-642-18381-2_14
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DOI: https://doi.org/10.1007/978-3-642-18381-2_14
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