Extensionality of the RCC8 Composition Table

This paper is mainly concerned with the RCC8 composition table entailed by the Region Connection Calculus (RCC), a well-known formalism for Qualitative Spatial Reasoning. This table has been independently generated by Egenhofer in the context of Geographic Information Systems. It has been known for some time that the table is not extensional for each RCC model. This paper however shows that the Egenhofer model is indeed an extensional one for the RCC8 composition table. Moreover this model is the maximal extensional one for the RCC8 composition table in a sense.