Diving into the queue
| Autor: | Martin Kutrib, Matthias Wendlandt, Andreas Malcher, Simon Beier |
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| Rok vydání: | 2018 |
| Předmět: |
Discrete mathematics
Finite-state machine Hierarchy (mathematics) Computer science Head (linguistics) General Mathematics 0102 computer and information sciences 01 natural sciences Computer Science Applications Automaton Decidability Computer Science::Performance 010201 computation theory & mathematics Formal language Computer Science::Networking and Internet Architecture Queue Finite set Software |
| Zdroj: | RAIRO - Theoretical Informatics and Applications. 52:89-110 |
| ISSN: | 1290-385X 0988-3754 |
| DOI: | 10.1051/ita/2018009 |
| Popis: | We introduce and study the model of diving queue automata which are basically finite automata equipped with a storage medium that is organized as a queue. Additionally, two queue heads are provided at both ends of the queue that can move in a read-only mode inside the queue. In particular, we consider suitable time constraints and the case where only a finite number of turns on the queue is allowed. As one main result we obtain a proper queue head hierarchy, that is, two heads are better than one head, and one head is better than no head. Moreover, it is shown that the model with one queue head, finitely many turns, and no time constraints as well as the model with two queue heads, possibly infinitely many turns, and time constraints is captured by P and has a P-complete membership problem. We obtain also that a subclass of the model with two queue heads is already captured by logarithmic space. Finally, we consider decidability questions and it turns out that almost nothing is decidable for the model with two queue heads, whereas we obtain that at least emptiness and finiteness are decidable for subclasses of the model with one queue head. |
| Databáze: | OpenAIRE |
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