This mechanism enables users even to query for namespaces (concrete URIs not aliases) and to provide variables in namespaces. For instance, the following query asks for all namespaces X that contain a concept person.

?- ?X [_localName->Person, _namespace->?N].

The following inference rule integrates knowledge from different ontologies using the namespace mechanism (and a so called Skolem-function).

person(?Name)[?Attr -> ?Value] :-

         (EXIST ?X

                 ?X:finance#Person[?Attr -> ?Value, finance#name -> ?Name] OR

                 ?X:cars#Person[?Attr -> ?Value, cars#name -> ?Name]).