Function pm#authoring_time__authoringtime (description_content/medium/container -> time_measure)
  subtype:  authoring_date
  supertype:  relation_from_description_content/medium/container (description_content/medium/container,*)
     supertype:  relation_from/to_thing_of_common_kind (*)  this type permits to categorize relations according to their signatures and hence offers (i) a concise way to set essential exclusion relations, and (ii) a systematic and easy-to-follow categorization
        >part of:  relation__related_thing__relatedthing___related_with  type for any relation (unary, binary, ..., *-ary) and instance of pm#relation_type
  supertype:  Date (? -> 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:  attributive_relation__attributiverelation (*)  like pm#binary_relation, this type mostly exists to categorize what cannot be categorized elsewhere
        supertype:  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:  relation__related_thing__relatedthing___related_with  type for any relation (unary, binary, ..., *-ary) and instance of pm#relation_type