Function pm#publish_date__publishdate (? -> pm#entity)
  supertype:  dc#Date (? -> pm#entity)  to specify a date associated with an event in the life cycle of a resource; in WebKB, pm#time or other MORE PRECISE RELATIONS SHOULD BE USED INSTEAD
     supertype:  pm#attributive_relation__attributiverelation (*)  like pm#binary_relation, this type mostly exists to categorize what cannot be categorized elsewhere
        supertype:  pm#relation_playing_a_special_role (*)  this type permits to categorize relations according to their roles ; this is a traditional but quite subjective way of categorizing relations
           >part of:  pm#relation__related_thing__relatedthing___related_with  type for any relation (unary, binary, ..., *-ary) and instance of pm#relation_type