Relation pm#constitution (?,?)
  supertype:  partial_ordering_relation  this category only serves structuration purposes: it is instance of pm#partial_ordering_relation_type which is not instance of pm#class_of_inheritable_relation_type
  instance of:  partial_ordering_relation_type
  subtype:  substance (? -> ?)
     subtype:  matter (physical_entity -> physical_entity_part_or_substance)
  subtype:  constituted_by__constitutedby__substance___K__k (entity,entity)
     subtype:  has_member__hasmember (entity,entity)