Pinpointing in the Description Logic EL+

Axiom pinpointing has been introduced in description logics (DLs) to help the user understand the reasons why consequences hold by computing minimal subsets of the knowledge base that have the consequence in question. Until now, the pinpointing approach has only been applied to the DL ALC and some of its extensions. This paper considers axiom pinpointing in the less expressive DL EL+ , for which subsumption can be decided in polynomial time. More precisely, we consider an extension of the pinpointing problem where the knowledge base is divided into a static part, which is always present, and a refutable part, of which subsets are taken. We describe an extension of the subsumption algorithm for EL+ that can be used to compute all minimal subsets of (the refutable part of) a given TBox that imply a certain subsumption relationship. The worst-case complexity of this algorithm turns out to be exponential. This is not surprising since we can show that a given TBox may have exponentially man...

• Type: Conference
• Year: 2007
• Where: KI
• Authors: Franz Baader, Rafael Peñaloza, Boontawee Suntisrivaraporn
• Keywords: Axiom Pinpointing, KI 2007, Knowledge Base, Minimal Subset