Method and apparatus for domain specialization in a document type definition

A method and apparatus for domain specialization of document type definitions (DTDs) are provided. With the method and apparatus, a user may define a domain specialized DTD using specialized DTD elements derived from base DTD elements that are supported by a community of users. The specialized DTD for the domain is created by defining new elements that have a formal relationship with the base DTD elements. A shell DTD is created that references the base DTD elements and the specialized DTD elements. The shell DTD redefines the entity associated with the base DTD element to add the specialized DTD element. The shell DTD further includes a domain list that identifies all of the domains associated with the shell DTD. Since the shell DTD associates the entity with both the base DTD element and the specialized DTD element, and because content models reference elements by the use of the entity to reference the corresponding element, the specialized element may be used anywhere that the general element may be used.