Typed properties and negative typed properties: dealing with type observations and negative statements in the CIDOC CRM

During condition and collection surveys in memory organisations, surveyors observe the absence of features on collection items. They also observe types of multiple components as single instances given that their large number makes them difficult to be captured as separate instances. Such observations are significant to researchers, documented in registration forms but are not easy to model in popular ontologies such as the CIDOC CRM. In this paper the nature of absence is explored from an ontology point of view alongside the role of the Open World and Close World Assumptions in knowledge bases. A proposal is then formulated for the use of special properties within the CIDOC CRM ontology, namely ‘typed properties’ and ‘negative typed properties’ which allow modelling the typology of multiple instances and the absence of instances. The nature of these properties is then explored in relation to their correspondence to longer property paths, their hierarchical arrangement and relevance to thesauri. First order logic statements are used to describe these properties. Examples from bookbinding structures are used given the significance of such observations in the field of bookbinding history. The paper concludes with reference to ongoing implementation work and a summary of findings.