Ontologies have been used for formal representation of knowledge for many years now. One possible knowledge representation language for ontologies is the OWL 2 Web Ontology Language, informally OWL 2. The OWL specification includes the definition of variants of OWL, with different levels of expressiveness. OWL DL and OWL Lite are based on Description Logics, for which sound and complete reasone...

In this paper we discuss three problems with OWL syntax that repeatedly surface in practice. The first problem is that OWL does not allow for explicit declarations—assertions that a certain class, property, or an individual exists in an ontology. This aspect of the OWL standard was often misinterpreted, which caused design errors in OWL APIs; moreover, the lack of declarations makes devising an...

Since achieving W3C recommendation status in 2004, the Web Ontology Language (OWL) has been successfully applied to many problems in computer science. Practical experience with OWL has been quite positive in general; however, it has also revealed room for improvement in several areas. We systematically analyze the identified shortcomings of OWL, such as expressivity issues, problems with its sy...

Java2OWL is a Java software library for synchronising Java class hierarchies with OWL concept hierarchies. With a few extra annotations in Java class files, the Java2OWL library can automatically map Java class hierarchies to OWL ontologies. The instances of these Java classes are automatically mapped to OWL individuals and vice versa. OWL reasoners can be used as query processors to retrieve i...

As stated in [5], a major design goal for PR-OWL was to attain compatibility with OWL. However, this goal has been only partially achieved as yet, primarily due to several key issues not fully addressed in the original work. This paper describes several important issues of compatibility between PR-OWL and OWL, and suggests approaches to deal with them. To illustrate the issues and how they can ...