In the past, we have proposed the theta-connection method for the description logic (DL) ALC, the ALC theta–CM, which will be briefly explained, together with an introduction of the first-order connection calculus and Description Logic. The ALC theta–CM replaces the usage of Skolem terms and unification by additional annotation and introduces blocking through a new rule in the connection calculus, to ensure termination in the case of cyclic ontologies. RACCOON, the reasoner which embodied this calculus, displayed surprisingly promising performance in a benchmarking given the fact that it consists of an engine which has no typical DL optimizations. In this work, we enhance this calculus and its representation to take on ALCHQ=, an extended DL fragment that includes role hierarchies, qualified number restrictions and (in)equalities. The main novelty of the new calculus lies in the introduction of equality, as well as in the redefinition of connection to accommodate number restrictions, either explicitly or expressed through equality. The new calculus uses the Eq system, thus introducing substitutivity axioms for each concept or role name. The application of Bibel’s equality connections appears here as a first solution to deal with equality. Fred Freitas

Centro de Informática - CIn Universidade Federal de Pernambuco - UFPE - Brazil

Research interests: Ontologies, semantic web, description logic reasoning

“To be normal is the ideal aim for the unsuccessful.” “Ser normal é a meta ideal dos fracassados.”

  • C.G.Jung