Relation pm#relation_to_situation (*,pm#situation)  in WebKB, prefer using relations "from" a situation
  exclusion:  pm#spatial_relation_to_entity_with_spatial_feature  pm#relation_to_time  pm#relation_to_collection  pm#relation_to_attribute_or_quality_or_measure
  subtype: {pm#relation_from_time_to_situation pm#relation_from_situation_to_situation}
  similar_to:  lis#participation  lis#involvement_by_reference
  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