Relation owl#prior_version__priorversion (pm#ontology,pm#ontology)
  supertype:  pm#relation_to_another_ontology (pm#ontology,pm#ontology)
     supertype:  pm#relation_from_an_ontology (pm#ontology,*)
        supertype:  pm#relation_from_collection (pm#collection,*)
           supertype:  pm#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:  pm#relation__related_thing__relatedthing___related_with  type for any relation (unary, binary, ..., *-ary) and instance of pm#relation_type
           supertype:  pm#what_relation (*)
              supertype:  pm#wh-/how_relation (*)  this type permits to categorize relations according to the usual who/what/why/where/when/how questions ; this is a traditional but very subjective and ineffective 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
     supertype:  pm#relation_between_collections (pm#collection,pm#collection+)
        supertype:  pm#relation_from_collection (pm#collection,*)
        supertype:  pm#relation_to_collection (*,pm#collection)
           supertype:  pm#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
           supertype:  pm#what_relation (*)