Multi-Head Finite Automata: Characterizations, Concepts and Open Problems
نویسندگان
چکیده
منابع مشابه
Multi-Head Finite Automata: Characterizations, Concepts and Open Problems
Multi-head finite automata were introduced in [36] and [38]. Since that time, a vast literature on computational and descriptional complexity issues on multi-head finite automata documenting the importance of these devices has been developed. Although multi-head finite automata are a simple concept, their computational behavior can be already very complex and leads to undecidable or even non-se...
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The 2-way quantum finite automaton introduced by Kondacs and Watrous[KW97] can accept non-regular languages with bounded error in polynomial time. If we restrict the head of the automaton to moving classically and to moving only in one direction, the acceptance power of this 1-way quantum finite automaton is reduced to a proper subset of the regular languages. In this paper we study two differe...
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We develop a framework on multi-head nite automata that allows us to study the relation of parallel logarithmic time and sequential logarithmic space in a uniform and nonuniform setting in more detail. In both settings it turns out that NC 1 requires data-independent computations|the movement of the input-heads only depends on the length of the input|whereas logarithmic space is caught with dat...
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One of the main topics of descriptional complexity is the question of how the size of the description of a formal language varies when being described by different formalisms. A fundamental result is the exponential trade-off between the number of states of nondeterministic (NFA) and deterministic finite automata (DFA) (see, for example, [12]). Additional exponential and double-exponential trad...
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In this paper, we present a parallel speed-up of a simple, yet significantly powerful, sequential model by cellular automata. The simulated model is called oblivious multi-head finite automata and is characterized by the fact that the trajectory of the heads only depends on the length of the input word. While the original k-head finite automaton works in time O(nk), its corresponding cellular a...
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ژورنال
عنوان ژورنال: Electronic Proceedings in Theoretical Computer Science
سال: 2009
ISSN: 2075-2180
DOI: 10.4204/eptcs.1.9