Structure of this thesis

First we will summarize the state of the art in the ontology and theory of situations in chapter 3. In section 3.1 we will introduce shortly situation calculus as it has been developed by McCarthy and Hayes. In 3.2 we will introduce situation theory as it has been developed by Barwise and Perry.

Chapter 4 gives an overview over ontology in philosophy and in computer science. Our reference ontology GOL will be introduced in this chapter.

Chapter 5 is the central part of this thesis. There we will develop our own theory of situoids and situations within the ontology of GOL. Section 5.1 will introduce infons, 5.2 situoids. Central to 5.2 is the discussion of comprehension, the relationship between parts and wholes and the relation of situoids to reality and worlds, but other properties of situoids will be discussed, too. The rest of chapter 5 discusses situations and their models, but some derived categories like processes and changes as well.

Chapter 6 discusses the theory that has been developed in 5. Two important applications are shown: How the theory can be used to give a semantic for natural language, and how it can be used to introduce modality into GOL. Later, some remarks are made concerning the similarities and differences to situation theory as developed by Barwise and Perry.

Chapter 7 is a review on the thesis. The contributions made are listed, and ideas for future research are given.