Relation owl#union_of__unionof (rdfs#class,rdf#list)  for unionOf(X,L) read: X is the union of the classes in the list L; i.e. if something is in any of the classes in L, it is in X, and vice versa
  subtype:  daml#disjoint_union_of  for disjointUnionOf(X,L) read: X is the disjoint union of the classes in the list L: (a) for any c1 and c2 in L, disjointWith(c1,c2), and (b) i.e. if something is in any of the classes in L, it is in X, and vice versa
  related_to:  sumo#exhaustive_decomposition (owl)
  supertype:  pm#relation_from_class_to_collection (rdfs#class,pm#collection)
     supertype:  pm#relation_from_type_to_collection (pm#type,pm#collection)
        supertype:  pm#relation_between_collections (pm#collection,pm#collection+)
           supertype:  pm#relation_from_collection (pm#collection,*)
              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#what_relation (*)
                 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
           supertype:  pm#relation_to_collection (*,pm#collection)
              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
              supertype:  pm#what_relation (*)
        supertype:  pm#relation_from_type (pm#type,*)  type of relations from a concept/relation type, i.e. in RDFS terminology, from a class or a property
           supertype:  pm#relation_from_collection (pm#collection,*)
     supertype:  pm#relation_from_class (rdfs#class,*)
        supertype:  pm#relation_from_type (pm#type,*)  type of relations from a concept/relation type, i.e. in RDFS terminology, from a class or a property