Pushdown automaton

About: Pushdown automaton is a(n) research topic. Over the lifetime, 1868 publication(s) have been published within this topic receiving 35399 citation(s).

The mathematical theory of L systems

Abstract: The paper gives a survey of the different areas of the theory of developmental systems and languages. It is organized in such a way that it discusses typical results obtained in each particular problem area. The results quoted may not always be the most important ones but they are quite representative for the direction of research in this theory. Proofs are not given and, consequently, the basic techniques for solving problems in this theory are not discussed. An attempt has been made to cover also the most recent results. Most of the results have not yet appeared in print. To appear in J. Tou (ed. ), Advances in Information Systems Science, Plenum Press.

Reachability Analysis of Pushdown Automata: Application to Model-Checking

Abstract: We apply the symbolic analysis principle to pushdown systems. We represent (possibly infinite) sets of configurations of such systems by means of finite-state automata. In order to reason in a uniform way about analysis problems involving both existential and universal path quantification (such as model-checking for branching-time logics), we consider the more general class of alternating pushdown systems and use alternating finite-state automata as a representation structure for sets of their configurations. We give a simple and natural procedure to compute sets of predecessors using this representation structure. We incorporate this procedure into the automata-theoretic approach to model-checking to define new model-checking algorithms for pushdown systems against both linear and branching-time properties. From these results we derive upper bounds for several model-checking problems as well as matching lower bounds.

Fast LTL to Büchi Automata Translation

Abstract: We present an algorithm to generate Buchi automata from LTL formulae. This algorithm generates a very weak alternating co-Buchi automaton and then transforms it into a Buchi automaton, using a generalized Buchi automaton as an intermediate step. Each automaton is simplified on-the-fly in order to save memory and time. As usual we simplify the LTL formula before any treatment. We implemented this algorithm and compared it with Spin: the experiments show that our algorithm is much more efficient than Spin. The criteria of comparison are the size of the resulting automaton, the time of the computation and the memory used. Our implementation is available on the web at the following address: http://verif.liafa.jussieu.fr/ltl2ba

Visibly pushdown languages

Abstract: We propose the class of visibly pushdown languages as embeddings of context-free languages that is rich enough to model program analysis questions and yet is tractable and robust like the class of regular languages. In our definition, the input symbol determines when the pushdown automaton can push or pop, and thus the stack depth at every position. We show that the resulting class Vpl of languages is closed under union, intersection, complementation, renaming, concatenation, and Kleene-*, and problems such as inclusion that are undecidable for context-free languages are Exptime-complete for visibly pushdown automata. Our framework explains, unifies, and generalizes many of the decision procedures in the program analysis literature, and allows algorithmic verification of recursive programs with respect to many context-free properties including access control properties via stack inspection and correctness of procedures with respect to pre and post conditions. We demonstrate that the class Vpl is robust by giving two alternative characterizations: a logical characterization using the monadic second order (MSO) theory over words augmented with a binary matching predicate, and a correspondence to regular tree languages. We also consider visibly pushdown languages of infinite words and show that the closure properties, MSO-characterization and the characterization in terms of regular trees carry over. The main difference with respect to the case of finite words turns out to be determinizability: nondeterministic Buchi visibly pushdown automata are strictly more expressive than deterministic Muller visibly pushdown automata.

Handbook of Weighted Automata

Abstract: Weighted finite automata are classical nondeterministic finite automata in which the transitions carry weights These weights may model, for example, the cost involved when executing a transition, the resources or time needed for this, or the probability or reliability of its successful execution Weights can also be added to classical automata with infinite state sets like pushdown automata, and this extension constitutes the general concept of weighted automata Since their introduction in the 1960s they have stimulated research in related areas of theoretical computer science, including formal language theory, algebra, logic, and discrete structures Moreover, weighted automata and weighted context-free grammars have found application in natural-language processing, speech recognition, and digital image compression This book covers all the main aspects of weighted automata and formal power series methods, ranging from theory to applications The contributors are the leading experts in their respective areas, and each chapter presents a detailed survey of the state of the art and pointers to future research The chapters in Part I cover the foundations of the theory of weighted automata, specifically addressing semirings, power series, and fixed point theory Part II investigates different concepts of weighted recognizability Part III examines alternative types of weighted automata and various discrete structures other than words Finally, Part IV deals with applications of weighted automata, including digital image compression, fuzzy languages, model checking, and natural-language processing Computer scientists and mathematicians will find this book an excellent survey and reference volume, and it will also be a valuable resource for students exploring this exciting research area