AAAI Publications, Twenty-First International Joint Conference on Artificial Intelligence

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Decomposition of Declarative Knowledge Bases with External Functions
Thomas Eiter, Michael Fink, Thomas Krennwallner

Last modified: 2009-06-25


We present a method to decompose a declarative knowledge base, given by a logic program under Answer Set Semantics with access to external sources. It overcomes the ineffectiveness of current methods due to a lack of structural information about these sources, viewed as black boxes, by exploiting independency information in accesses to them.  To this end, we develop a generic notion of domain independence that allows to restrict the evaluation domain and, as a consequence, to prune unnecessary dependency assumptions between atoms. This leads to increased decomposability, which we demonstrate by an evaluation method for HEX-programs based on program rewriting. Experiments show that this may yield large performance gains. While developed for a particular formalism, the notions and ideas of this  paper might be adapted to related formalisms as well.


Knowledge Representation; Nonmonotonic Reasoning; Logic Programming

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