A Rule-Based Approach to Specifying Preferences over Conflicting Facts and Querying Inconsistent Knowledge Bases

TL;DR

This paper introduces a declarative rule-based framework for specifying and computing preferences over conflicting facts in inconsistent knowledge bases, enabling meaningful query answering through prioritized repairs.

Contribution

It proposes a novel rule-based method for defining and computing priority relations, addressing cycle issues, and integrating this into an answer set programming system for querying inconsistent KBs.

Findings

Framework effectively specifies preferences and resolves cycles.

Preliminary implementation demonstrates practical query answering.

Experimental results show promising performance of the approach.

Abstract

Repair-based semantics have been extensively studied as a means of obtaining meaningful answers to queries posed over inconsistent knowledge bases (KBs). While several works have considered how to exploit a priority relation between facts to select optimal repairs, the question of how to specify such preferences remains largely unaddressed. This motivates us to introduce a declarative rule-based framework for specifying and computing a priority relation between conflicting facts. As the expressed preferences may contain undesirable cycles, we consider the problem of determining when a set of preference rules always yields an acyclic relation, and we also explore a pragmatic approach that extracts an acyclic relation by applying various cycle removal techniques. Towards an end-to-end system for querying inconsistent KBs, we present a preliminary implementation and experimental evaluation of the framework, which employs answer set programming to evaluate the preference rules, apply the desired cycle resolution techniques to obtain a priority relation, and answer queries under prioritized-repair semantics.