Relation pm#equivalence_relation__equivalencerelation (?,?)  this category only serves structuration purposes: it is instance of pm#equivalence_relation_type which is not instance of pm#class_of_inheritable_relation_type
  supertype:  pm#reflexive_relation  pm#symmetric_relation  pm#transitive_relation
  subtype:  pm#similar (?,?)  DO NOT USE SUCH A RELATION TYPE DIRECTLY
     subtype:  pm#closely_similar__closelysimilar (?,?)  the '~' link in WebKB-2: currently only used between categories for Greek gods and their Roman counterparts, and between some types from the 3D (endurantist) approach and their counterparts from the 4D (perdurantist) approach or the ?D (vague/unspecified) approach)
     subtype:  pm#loosely_similar__looselysimilar (?,?)
     subtype:  pm#related_to__relatedto (?,?)  the '&' link in WebKB-2 (currently used for representing a sumo#related_internal_concept relation)
        subtype:  sumo#related_internal_concept (?,?)  the two arguments are related concepts within the SUMO, i.e. there is a significant similarity of meaning between them; to indicate a meaning relation between a SUMO concept and a concept from another source, use sumo#related_external_concept
  subtype:  pm#equal (?,?)  "=" in KIF; true if the 1st argument is identical to the 2nd
     subtype:  owl#same_as (?,?)  MORE PRECISE TYPES THAN THIS ONE SHOULD BE USED
        subtype:  pm#same_type_as (pm#type,pm#type)
           subtype:  owl#equivalent_class (rdfs#class,rdfs#class)  in WebKB, use the link '='
           subtype:  owl#equivalent_property (pm#binary_relation_type,pm#binary_relation_type)  in WebKB, use the link '='
        subtype:  owl#same_individual_as (?,?)
  subtype:  pm#equivalence__equivalentTo___iff__iff (pm#description,pm#description)
  subtype:  sumo#copy (sumo#object,sumo#object)  relates an object to an exact copy of the object, where an exact copy is indistinguishable from the original with regard to every property except (possibly) spatial and/or temporal location
  subtype:  sumo#equivalent_content_class (?,?)
  subtype:  sumo#equivalent_content_instance (?,?)
  subtype:  sumo#cooccur (?,?)
  subtype:  sumo#family_relation (?,?)