Relation rst#purpose (description_content/medium/container,description_content/medium/container)  situation that the described action is intended to reach
  exclusion:  volitional_cause  non-volitional_cause
  supertype:  cause (description_content/medium/container,description_content/medium/container)  not a subtype of pm#cause since pm#cause connects situations
     supertype:  subject_matter_rhetorical_relation (description_content/medium/container,description_content/medium/container)  connect to details for making a better description
        supertype:  rhetorical_relation (description_content/medium/container,description_content/medium/container)  main sources: the Rhetorical Structure Theory (RST) and the PENMAN ontology; DO NOT USE such fuzzy relations: instead, use relations from/to situations!
           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:  purpose (?,?)
     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
     supertype:  why_relation__whyrelation (*)
        supertype:  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:  relation__related_thing__relatedthing___related_with  type for any relation (unary, binary, ..., *-ary) and instance of pm#relation_type