Michel Ludwig & Dirk Walther

Logic & Computation

Week One - 11.00-12.30 - Level: I

Room: N8


Ontologies are widely used to represent knowledge. They contain specifications of objects, concepts and relationships between them that are often formalised using a logic-based language over a vocabulary that is particular to an application domain. Numerous ontologies have already been developed in areas as broad and diverse as life sciences, health-care, and linguistics, among others.

Ontologies constantly evolve, they are regularly extended, corrected and refined. The challenges are now to provide automated tool support for their development and maintenance. In particular, ontology versioning is one of the most critical tasks. Current support from ontology editors is still mostly based on syntactic differences and does not capture the semantic differences between ontologies.

In this course, we will provide an overview of the state of the art in the area of analysing the logical difference of ontologies. The logical difference is taken to be the set of queries that produce different answers when evaluated over distinct versions of an ontology. The language and vocabulary of the queries can be adapted in such a way that exactly the differences of interest become visible, which can be independent of the syntactic representation of the ontologies. We will explain logical meta-properties of distinct notions of logical difference, and we will introduce the algorithms that have been developed to detect and represent logical differences.