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Implementation of directed acyclic word graph

Miroslav Balík (2002)

Kybernetika

An effective implementation of a Directed Acyclic Word Graph (DAWG) automaton is shown. A DAWG for a text T is a minimal automaton that accepts all substrings of a text T , so it represents a complete index of the text. While all usual implementations of DAWG needed about 30 times larger storage space than was the size of the text, here we show an implementation that decreases this requirement down to four times the size of the text. The method uses a compression of DAWG elements, i. e. vertices,...

Improved Lower Bounds on the Approximability of the Traveling Salesman Problem

Hans-Joachim Böckenhauer, Sebastian Seibert (2010)

RAIRO - Theoretical Informatics and Applications

This paper deals with lower bounds on the approximability of different subproblems of the Traveling Salesman Problem (TSP) which is known not to admit any polynomial time approximation algorithm in general (unless 𝒫 = 𝒩𝒫 ). First of all, we present an improved lower bound for the Traveling Salesman Problem with Triangle Inequality, Delta-TSP for short. Moreover our technique, an extension of the method of Engebretsen [11], also applies to the case of relaxed and sharpened triangle inequality, respectively,...

Imre Simon : an exceptional graduate student

Denis Thérien (2005)

RAIRO - Theoretical Informatics and Applications - Informatique Théorique et Applications

This short note reviews the main contributions of the Ph.D. thesis of Imre Simon. His graduate work had major impact on algebraic theory of automata and thirty years later we are in a good position to appreciate how sensitive he was in selecting good problems, and how clever in solving them!

Imre Simon: an exceptional graduate student

Denis Thérien (2010)

RAIRO - Theoretical Informatics and Applications

This short note reviews the main contributions of the Ph.D. thesis of Imre Simon. His graduate work had major impact on algebraic theory of automata and thirty years later we are in a good position to appreciate how sensitive he was in selecting good problems, and how clever in solving them!

Incremental DFA minimisation

Marco Almeida, Nelma Moreira, Rogério Reis (2014)

RAIRO - Theoretical Informatics and Applications - Informatique Théorique et Applications

We present a new incremental algorithm for minimising deterministic finite automata. It runs in quadratic time for any practical application and may be halted at any point, returning a partially minimised automaton. Hence, the algorithm may be applied to a given automaton at the same time as it is processing a string for acceptance. We also include some experimental comparative results.

Indécidabilité de la condition IRS

Jean-Michel Autebert, Joffroy Beauquier, Luc Boasson, Michel Latteux (1982)

RAIRO - Theoretical Informatics and Applications - Informatique Théorique et Applications

Indexed counter languages

J. Duske, M. Middendorf, R. Parchmann (1992)

RAIRO - Theoretical Informatics and Applications - Informatique Théorique et Applications

Induction and decision procedures.

Deepak Kapur, Jürgen Giesl, Mahadevan Subramaniam (2004)

RACSAM

Mechanization of inductive reasoning is an exciting research area in artificial intelligence and automated reasoning with many challenges. An overview of our work on mechanizing inductive reasoning based on the cover set method for generating induction schemes from terminating recursive function definitions and using decision procedures is presented. This paper particularly focuses on the recent work on integrating induction into decision procedures without compromising their automation.

Inf-datalog, modal logic and complexities

Eugénie Foustoucos, Irène Guessarian (2009)

RAIRO - Theoretical Informatics and Applications - Informatique Théorique et Applications

Inf-Datalog extends the usual least fixpoint semantics of Datalog with greatest fixpoint semantics: we defined inf-Datalog and characterized the expressive power of various fragments of inf-Datalog in [16]. In the present paper, we study the complexity of query evaluation on finite models for (various fragments of) inf-Datalog. We deduce a unified and elementary proof that global model-checking (i.e. computing all nodes satisfying a formula in a given structure) has 1. quadratic data complexity...

Inf-datalog, Modal Logic and Complexities

Eugénie Foustoucos, Irène Guessarian (2007)

RAIRO - Theoretical Informatics and Applications

Inf-Datalog extends the usual least fixpoint semantics of Datalog with greatest fixpoint semantics: we defined inf-Datalog and characterized the expressive power of various fragments of inf-Datalog in [CITE]. In the present paper, we study the complexity of query evaluation on finite models for (various fragments of) inf-Datalog. We deduce a unified and elementary proof that global model-checking (i.e. computing all nodes satisfying a formula in a given structure) has 1. quadratic data complexity...

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