منابع مشابه
Complementing Two-Way Finite Automata
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 hal...
متن کاملSize Complexity of Two-Way Finite Automata
This is a talk on the size complexity of two-way finite automata. We present the central open problem in the area, explain a motivation behind it, recall its early history, and introduce some of the concepts used in its study. We then sketch a possible future, describe a natural systematic way of pursuing it, and record some of the progress that has been achieved. We add little to what is alrea...
متن کاملFinite Automata With Restricted Two-Way Motion
We consider finite two-way automata and measure the use of twoway motion by counting the number of left moves in accepting computations. Restriction of the automata according to this measure allows us to study in detail the use of two-way motion for the acceptance of regular languages in terms of state complexity. The two-way spectrum of a given regular language is introduced. This quantity ref...
متن کاملTwo-Way Finite Automata: Old and Recent Results
The notion of two-way automata was introduced at the very beginning of automata theory. In 1959, Rabin and Scott [31] and, independently, Shepherdson [35], proved that these models, both in the deterministic and in the nondeterministic versions, have the same power of one-way automata, namely, they characterize the class of regular languages. In 1978, Sakoda and Sipser [32] posed the question o...
متن کاملOn Some Variations of Two-Way Probabilistic Finite Automata Models
Rabin [M. Rabin, Probabilistic finite automata, Information and Control (1963) 230–245] initiated the study of probabilistic finite automata (pfa). Rabin’s work showed a crucial role of the gap in the error bound (for accepting and non-accepting computations) in the power of the model. Further work resulted in the identification of qualitatively different error models (onesided error, bounded a...
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ژورنال
عنوان ژورنال: Information and Computation
سال: 2007
ISSN: 0890-5401
DOI: 10.1016/j.ic.2007.01.008