Topic
ω-automaton
About: ω-automaton is a research topic. Over the lifetime, 2299 publications have been published within this topic receiving 68468 citations. The topic is also known as: stream automaton & ω-automata.
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28 Aug 2005
TL;DR: This paper studies automata for unranked trees that are standard in database theory and shows that bottom-up deterministic stepwise tree automata yield the most succinct representations.
Abstract: Automata for unranked trees form a foundation for XML schemas, querying and pattern languages. We study the problem of efficiently minimizing such automata. We start with the unranked tree automata (UTAs) that are standard in database theory, assuming bottom-up determinism and that horizontal recursion is represented by deterministic finite automata. We show that minimal UTAs in that class are not unique and that minimization is np-hard. We then study more recent automata classes that do allow for polynomial time minimization. Among those, we show that bottom-up deterministic stepwise tree automata yield the most succinct representations.
40 citations
TL;DR: A new equivalence relation for stochastic automata denoted as exact performance equivalence is introduced and it is shown that this equivalence relationship preserves several important qualitative properties and also quantitative results.
40 citations
Journal Article•
40 citations
Book•
20 Sep 1989
TL;DR: This chapter discusses the structure Theory of Transition Algebras, the Structure and Behavior of Finite Automata, and General Alphabets: The Theory of Push-down Automata and Context-free Languages.
Abstract: 1 Concepts and Notations in Discrete Mathematics.- 2 The Structure Theory of Transition Algebras.- 3 The Structure and Behavior of Finite Automata.- 4 Transition Systems and Regular Events.- 5 Regular Canonical Systems.- 6 General Algebras: How They Function as Tree Acceptors and Push-down Automata.- 7 General Alphabets: The Theory of Push-down Automata and Context-free Languages.- Conclusion.- List of Symbols.- References.
39 citations
07 Feb 2006
TL;DR: It is shown that deterministic tree-walking automata are weaker than nondeterministic tree, walking automata.
Abstract: Tree-walking automata are a natural sequential model for recognizing languages of finite trees. Such automata walk around the tree and may decide in the end to accept it. It is shown that deterministic tree-walking automata are weaker than nondeterministic tree-walking automata.
39 citations