1. Upper Ontology Summit March 15, 2006 Michael Gruninger Semantic Technologies Laboratory University of Toronto

2. Goals As a prelude to creating a common subset ontology that is compatible with all of the linked upper ontologies, we need to develop methods to relate the existing upper ontologies to each other.

3. Clashing Intuitions We need to move from “We believe that some set of concepts in the ontologies are equivalent” to –“We can prove that some set of concepts in the ontologies are equivalent”

4. Relationships among Ontologies Theory T 1 generalizes theory T 2 if and only if T 1 is definably interpretable in a theory T 3 and T 2 is a consistent extension of T 3. Problem: Given two theories T 1 and T 2, determine whether there exists a nontrivial theory that generalizes both. This is a well-posed logical problem

5. Requirements What do we need so that we can prove that one ontology is a generalization of another? –the ontology must consist of a consistent set of axioms –the ontology must axiomatize its intended models Evaluation of the relationships between ontologies is made using their axioms alone; it cannot rely on intended models of concepts that are not axiomatized. If the axioms of an ontology are insufficient to capture their users' intended semantics, then there is little progress that can be made towards integration

6. Verified Ontologies Research Challenge: Given the axioms of an upper ontology, prove that they are consistent prove that they axiomatize their intended models Ontologies with these properties exist PSL (ISO 18629) is a modular, extensible ontology capturing concepts required for process specification