The <hasInstance> element specifies that the contained subjects have an INSTANCE-OF relationship with the container subject. In an INSTANCE-OF hierarchy, the child subject is a specific entity or object and the parent subject is a type, kind, or class of entity or object.

Content models

See appendix for information about this element in OASIS document type shells.


- map/topicref subjectScheme/hasInstance


This example specifies that New York City, Reykjavik, and Moscow are each specific instances of a city.

    <subjectdef keys="city" navtitle="City">
      <subjectdef keys="nyc"       navtitle="New York City"/>
      <subjectdef keys="reykjavik" navtitle="Reykjavik"/>
      <subjectdef keys="moscow"    navtitle="Moscow"/>


The following attributes are available on this element: Universal attribute group , Link relationship attribute group (with a narrowed definition of @href, given below), @processing-role from Attributes common to many map elements , @navtitle from Topicref element attributes group , outputclass, @keys , and @keyref .

A pointer to the resource represented by the <topicref>. See The href attribute for detailed information on supported values and processing implications. References to DITA content cannot be below the topic level: that is, you cannot reference individual elements inside a topic. References to content other than DITA topics should use the @format attribute to identify the kind of resource being referenced.