Relation pm#exclusive_type__exclusivetype (pm#type,pm#type)  in WebKB, use the '!' link
  supertype:  pm#relation_from_type  type of relations from a concept/relation type, i.e. in RDFS terminology, from a class or a property
  equal:  dl#disjoint (pm)
  subtype:  pm#exclusive_class__exclusiveclas (rdfs#class,rdfs#class)  the 2 classes have no common subtype/instance; in WebKB, use the link '!'
     subtype:  pm#complement_class (rdfs#class -> rdfs#class)  if something is not in one of the classes, then it is in the other, and vice versa; in WebKB, use the link '/'
  subtype:  pm#closed_exclusion (pm#type -> pm#type)  the '/' link in the FT notation:  the two linked types either are respectively identical to pm#thing and pm#nothing (they are "complement types") or they subtype a same type and form a complete subtype partition
     subtype:  pm#complement_type (pm#type -> pm#type)  a supertype of owl#complement_of which can only connect RDFS/OWL classes
        subtype:  pm#complement_class (rdfs#class -> rdfs#class)  if something is not in one of the classes, then it is in the other, and vice versa; in WebKB, use the link '/'