Ontology in computer science

Ontology in computer science is distinct from, but similar to ontology in philosophy. While ontology in philosophy is the study of existence in general, in computer science, ``an ontology is the attempt to formulate an exhaustive and rigorous conceptual schema within a given domain, a typically hierarchical data structure containing all the relevant entities and their relationships and rules within that domain.''The Internet Community

Usually, while constructing a knowledge base for a certain domain, the designer has to restrict herself to a fixed vocabulary, some basic concepts, on which all other terms are based. This terminology is called an (domain specific) ontology. In this ontology, the relationship between those concepts will have to be specified. Important relations are $is-a$ and $part-of$.

After the concepts for one domain have been specified, the used concepts can be abstracted. Considering a domain for medical research, one concept could be disease. But a disease can also be considered some kind of process. A blood sample with a certain blood type could be viewed as simple matter or some substance with a property.

Every domain specific ontology can be abstracted, until no further abstraction seems possible. The result will be a terminology of the most fundamental categories of being, and a description of the relations thereof. This is called a top-level ontology. The question arises, if all domain specific ontologies converge to the same top-level ontology.

Before considering the main top-level ontology for this work, ``General Formal Ontology'', let us review some existing ontologies.