A closed map is a map of type DText(D) from some finite index set D to Object contents. Reference between objects consists of the occurrence of the referent's index in the referring object's content Text. Object indices are treated as Abstract Identifiers. The FDL is used as a repository for closed maps, and the usual method of interaction is to build and develop a Current Closed Map, which may be thought of as a closed map variable serving as the focus of a Session with the FDL. See Abstract Ids & Closed Maps and Closed Map Operations.
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