Relation dc#Description (?,pm#entity)  to specify an account of the content of a resource; in WebKB, pm#topic or pmdescr SHOULD BE USED INSTEAD
  exclusion:  dc#Type
  supertype:  pm#binary_relation (pm)  in WebKB, most relation types are binary and some have a variable number of arguments (as in KIF), hence this type is currently only specialized by types that I do not want to see as direct subtypes of pm#relation
  subtype:  pm#topic (?,pm#entity)
     subtype:  pm#annotation (?,pm#description_content/medium/container)
        subtype:  pm#descr (?,pm#description_content/medium/container)  for connecting an object to a formal representation of it, e.g., a representation written with a fcg
        subtype:  dc#Subject (pm#description,pm#entity)  to specify 1 or several topics; in WebKB, pm#descr SHOULD BE USED INSTEAD
        subtype:  pm#origin (?,pm#description_content/medium/container)
        subtype:  pm#use (?,pm#description_content/medium/container)
        subtype:  pm#advantage (?,pm#description_content/medium/container)
        subtype:  pm#disadvantage (?,pm#description_content/medium/container)
        subtype:  pm#definition (?,pm#description_content/medium/container)  see also #definition
           subtype:  rst#definition (pm#description_content/medium/container,pm#description_content/medium/container)  a logical relation should be used instead of this relation
        subtype:  pm#role (?,pm#description_content/medium/container)
        subtype:  pm#requirement (?,pm#description_content/medium/container)
        subtype:  pm#issue (?,pm#description_content/medium/container)
        subtype:  pm#trap (?,pm#description_content/medium/container)
  subtype:  pm#url (?,pm#URL)
  subtype:  pm#file_or_file_element (?,pm#description_container)
     subtype:  pm#file (?,pm#document_element)
        subtype:  pm#home_page (?,pm#document_element)
     subtype:  pm#file_element (?,pm#document_element)
     subtype:  pm#descr_in__descrin (?,pm#description_container)  when a thing t has a description stored in a description container dc, there is a relation pm#descr_in from t to dc
        subtype:  pm#descr_container__description_support___descr_support (pm#description,pm#description_container)  permits to associate a statement with an object on which it is represented
  subtype:  owl#version_info__versioninfo (? -> pm#entity)  generally, a string giving information about this version; e.g., RCS/CVS keywords
  subtype:  pm#title (? -> pm#string)  for connecting an object to its "title" in a natural language
  subtype:  rdfs#comment  for connecting an object to an informal representation of it, typically a node with a string inside; in WebKB, the FT and FCG notations permit to avoid using this relation type