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.

From Word Automata to Tree Automata

Abstract: Finite tree automata have now become a live research field both because of its features as a theoretical model of computation and its practical value in the parsing, query and verification of semi-structured data, such as XML. The aim of this work is to create a link between the already well-developed finite state automata over words and the finite automata over trees, by adding the mechanism of "invocation-and-return'' to a group of finite word automata. In this paper, the definition of this link and the resulted computation model, recursive tree automata, are formalized based on former works. Then we present an analysis for its expressiveness, closure properties and decision problems, to show that a group of finite word automata armed with this link has identical power of a tree automata. Also some applications of this link are introduced, involving a means of formalization of the W3C XML Schema.

On the Weakness of One-Way Quantum Pushdown Automata

Abstract: In general, quantum computation models are expected to be more powerful than classical counterparts. However, sometimes this is not the case.It is known that there exists some regular language which one-way quantum finite automata and one-way quantum counter automata cannot recognize. This is due to the restriction of reversibility which quantum models must satisfy. Thus, it is an interesting question: what kinds of quantum models suffer from/overcome the restriction? To tackle this problem, we focus on (empty-stack acceptance) one-way quantum pushdown automata, and show that there exists a regular language which one-way quantum pushdown automata cannot recognize. This implies adding a stack to one-way finite automata cannot overcome the restriction of reversibility if we adopt empty-stack acceptance as the acceptance mode.

Algorithms for the compilation of regular expressions into PLAs

Abstract: The language of regular expressions is a useful one for specifying certain sequential processes at a very high level. They allow easy modification of designs for circuits, like controllers, that are described by patterns of events they must recognize and the responses they must make to those patterns. This paper discusses the compilation of such expressions into specifications for programmable logic arrays (PLAs) that will implement the required function. A regular expression is converted into a nondeterministic finite automaton, and then the automaton states are encoded as values on wires that are inputs and outputs of a PLA. The translation of regular expressions into nondeterministic automata by two different methods is discussed, along with the advantages of each method. A major part of the compilation problem is selection of good state codes for the nondeterministic automata; one successful strategy and its application to microcode compaction is explained in the paper.

Automata and tree automata as (f1, f2)-coalgebras

Abstract: This paper extends existing relationships between automata and F-coalgebras to relationships between tree automata and (F1, F2)-coalgebras. The concept of an (F1, F2)-coalgebra generalizes that of an F-coalgebra as well as that of an F-algebra. The paper sketches some of the most important properties of the category Set(F1, F2) of (F1, F2)-coalgebras.

On asynchronous tree automata

Abstract: In this work we introduce asynchronous tree automata First isomorphically complete systems for the class of asynchronous tree automata are characterized with respect to the αi-products, then tree languages recognizable by asynchronous tree automata are described