Relation pm#doer/object/result/place (situation,?)
  subtype:  doer/object/result  from/to  place  path_length
  type:  case_relation_type  the class of predicates relating the spatially distinguished parts of a process. e.g., the agent, patient or destination of an action, the flammable substance in a burning process, or the water that falls in rain
  supertype:  case_relation__thematic_relation (situation,*)
     supertype:  relation_from_situation (situation,*)
        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