@inproceedings{GeskeWolf2010, author = {Geske, Ulrich and Wolf, Armin}, title = {Preface}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-41401}, year = {2010}, abstract = {The workshops on (constraint) logic programming (WLP) are the annual meeting of the Society of Logic Programming (GLP e.V.) and bring together researchers interested in logic programming, constraint programming, and related areas like databases, artificial intelligence and operations research. In this decade, previous workshops took place in Dresden (2008), W{\"u}rzburg (2007), Vienna (2006), Ulm (2005), Potsdam (2004), Dresden (2002), Kiel (2001), and W{\"u}rzburg (2000). Contributions to workshops deal with all theoretical, experimental, and application aspects of constraint programming (CP) and logic programming (LP), including foundations of constraint/ logic programming. Some of the special topics are constraint solving and optimization, extensions of functional logic programming, deductive databases, data mining, nonmonotonic reasoning, , interaction of CP/LP with other formalisms like agents, XML, JAVA, program analysis, program transformation, program verification, meta programming, parallelism and concurrency, answer set programming, implementation and software techniques (e.g., types, modularity, design patterns), applications (e.g., in production, environment, education, internet), constraint/logic programming for semantic web systems and applications, reasoning on the semantic web, data modelling for the web, semistructured data, and web query languages.}, language = {en} } @inproceedings{Cabalar2010, author = {Cabalar, Pedro}, title = {Existential quantifiers in the rule body}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-41476}, year = {2010}, abstract = {In this paper we consider a simple syntactic extension of Answer Set Programming (ASP) for dealing with (nested) existential quantifiers and double negation in the rule bodies, in a close way to the recent proposal RASPL-1. The semantics for this extension just resorts to Equilibrium Logic (or, equivalently, to the General Theory of Stable Models), which provides a logic-programming interpretation for any arbitrary theory in the syntax of Predicate Calculus. We present a translation of this syntactic class into standard logic programs with variables (either disjunctive or normal, depending on the input rule heads), as those allowed by current ASP solvers. The translation relies on the introduction of auxiliary predicates and the main result shows that it preserves strong equivalence modulo the original signature.}, language = {en} } @inproceedings{HerreHummel2010, author = {Herre, Heinrich and Hummel, Axel}, title = {A paraconsistent semantics for generalized logic programs}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-41496}, year = {2010}, abstract = {We propose a paraconsistent declarative semantics of possibly inconsistent generalized logic programs which allows for arbitrary formulas in the body and in the head of a rule (i.e. does not depend on the presence of any specific connective, such as negation(-as-failure), nor on any specific syntax of rules). For consistent generalized logic programs this semantics coincides with the stable generated models introduced in [HW97], and for normal logic programs it yields the stable models in the sense of [GL88].}, language = {en} } @inproceedings{Seipel2010, author = {Seipel, Dietmar}, title = {Practical Applications of Extended Deductive Databases in DATALOG*}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-41457}, year = {2010}, abstract = {A wide range of additional forward chaining applications could be realized with deductive databases, if their rule formalism, their immediate consequence operator, and their fixpoint iteration process would be more flexible. Deductive databases normally represent knowledge using stratified Datalog programs with default negation. But many practical applications of forward chaining require an extensible set of user-defined built-in predicates. Moreover, they often need function symbols for building complex data structures, and the stratified fixpoint iteration has to be extended by aggregation operations. We present an new language Datalog*, which extends Datalog by stratified meta-predicates (including default negation), function symbols, and user-defined built-in predicates, which are implemented and evaluated top-down in Prolog. All predicates are subject to the same backtracking mechanism. The bottom-up fixpoint iteration can aggregate the derived facts after each iteration based on user-defined Prolog predicates.}, language = {en} } @inproceedings{Brass2010, author = {Brass, Stefan}, title = {Range restriction for general formulas}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-41521}, year = {2010}, abstract = {Deductive databases need general formulas in rule bodies, not only conjuctions of literals. This is well known since the work of Lloyd and Topor about extended logic programming. Of course, formulas must be restricted in such a way that they can be effectively evaluated in finite time, and produce only a finite number of new tuples (in each iteration of the TP-operator: the fixpoint can still be infinite). It is also necessary to respect binding restrictions of built-in predicates: many of these predicates can be executed only when certain arguments are ground. Whereas for standard logic programming rules, questions of safety, allowedness, and range-restriction are relatively easy and well understood, the situation for general formulas is a bit more complicated. We give a syntactic analysis of formulas that guarantees the necessary properties.}, language = {en} }