The dlv System: Model Generator and Advanced Frontends 

(system description)

by Simona Citrigno, Thomas Eiter, Wolfgang Faber, Georg Gottlob, Christoph Koch, 
Nicola Leone, Cristinel Mateis, Gerald Pfeifer, and Francesco Scarcello 
Technische Universität Wien, Austria, Universität 
Giessen, Germany, Univ. della Calabria, Rende, Italy 

Abstract 

During the last years, much research has been done concerning semantics and complexity of Dis-
junctive Deductive Databases (DDDBs). While DDDBs - function-free disjunctive logic programs 
with negation in rule bodies allowed - are now generally considered a powerful tool for common-
sense reasoning and knowledge representation, there has been a shortage of actual (let alone effi-
cient) implementations ([ST94, ADN97]). This paper presents a brief overview of the architecture 
of the dlv (datalog with disjunction) system system currently developed at TU Wien in the FWF 
project P11580-MAT "A Query System for Disjunctive Deductive Databases", especially focusing 
on the Model Generator - the "heart" of the dlv system - and the integrated frontends for 
diagnostic reasoning and SQL3.

Keywords: Deductive Databases Systems, Disjunctive Logic Programming, Non-Monotonic Rea-
soning, Implementation.