System description: DLV

ACM Transactions on Computational Logic, 2006

Disjunctive Logic Programming (DLP) is an advanced formalism for knowledge representation and reasoning, which is very expressive in a precise mathematical sense: it allows to express every property of finite structures that is decidable in the complexity class Σ P 2 (NP NP ). Thus, under widely believed assumptions, DLP is strictly more expressive than normal (disjunction-free) logic programming, whose expressiveness is limited to properties decidable in NP. Importantly, apart from enlarging the class of applications which can be encoded in the language, disjunction often allows for representing problems of lower complexity in a simpler and more natural fashion.

Lecture Notes in Computer Science, 2003

2000

DLV is an efficient logic programming and nonmonotonic reasoning (LPNMR) system with advanced knowledge representation mechanisms and interfaces to classic relational database systems. Its core language is disjunctive datalog (function-free disjunctive logic programming) under the Answer Set Semantics with integrity constraints, both default and strong (or explicit) negation, and queries. Integer arithmetics and various built-in predicates are also supported.

2004

DLV is a powerful system for knowledge representation and reasoning which supports Answer Set Programming (ASP) -a logicbased programming paradigm for solving problems in a fully declarative way. DLV is widely used in academy, and, importantly, it has been fruitfully employed in many relevant industrial applications. As for the other main-stream ASP systems, in the first phase of the computation DLV eliminates the variables, generating a ground program which is semantically equivalent to the original one but significantly smaller than the Herbrand Instantiation, in general. This phase, called 'grounding', plays a key role for the successful deployment in real-world contexts. In this work we present I-DLV, a brand new version of the intelligent grounder of DLV. While relying on the solid theoretical foundations of its predecessor, it has been completely redesigned and re-engineered, both in algorithms and data structures; it now features full support to ASP-Core2 standard language, increased flexibility and customizability, significantly improved performances, and an extensible design that eases the incorporation of language updates and optimization techniques. I-DLV results in a stable and efficient ASP instantiator that turns out to be a full-fledged deductive database system. We describe the main features of I-DLV and carry out experimental activities for assessing applicability and performances.

2000

The attractiveness of Answer Set Programming,(ASP) and re- lated paradigms,for declarative problem,solving is consider- ably due to the availability of highly efficient yet easy-to-use implementations. A major driving force for the development and improvement,of tools are standardized problem,repre- sentations, for several reasons. First, they relieve developers from the burden of inventing their own,input formats. Sec- ond, they establish interoperability

2004

The DLV system is currently employed in projects on data integration–a challenging application area for Answer Set Programming. The present system description illustrates some new optimization techniques, which significantly enhance the general performance of DLV, and especially in the context of data integration.

Ki, 2005

Answer Set Programming (ASP) is a declarative paradigm for solving search problems appearing in knowledge representation and reasoning. To solve a problem, a programmer designs a logic program so that models of the program determine solutions to the problem. ASP has been identified in the late 1990s as a subarea of logic programming and is becoming one of the fastest growing fields in knowledge representation and declarative programming. Major advantages of ASP are (1) its simplicity, (2) its ability to model effectively incomplete specifications and closure constraints, and (3) its relation to constraint satisfaction and propositional satisfiability, which allows one to take advantage of advances in these areas when designing solvers for ASP systems.

Although ASP systems have been extended in many directions , they still miss features which may be helpful towards industrial applications, like capabilities of quickly introduce new predefined constructs or to deal with compound data structures and module. We show here an implementation on top of the DLV system of DLP T language, which features increased declarativity, code readability, compactness and reusability.