Relation pm#from/to (pm#situation,pm#entity)
  subtype:  pm#source  pm#recipient  pm#from/to_place  sumo#origin  sumo#destination
  supertype:  pm#doer/object/result/place (pm#situation,?)
     supertype:  pm#case_relation__thematic_relation (pm#situation,*)
        supertype:  pm#relation_from_situation (pm#situation,*)
           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#where_relation__whererelation (*)  where, from/to where, ...
     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