Relation 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)
  exclusion:  loosely_similar
  supertype:  similar (?,?)  DO NOT USE SUCH A RELATION TYPE DIRECTLY
     supertype:  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:  reflexive_relation__reflexiverelation (?,?)  this category only serves structuration purposes: it is instance of pm#reflexive_relation_type which is not instance of pm#class_of_inheritable_relation_type
           supertype:  binary_relation_with_particular_mathematical_property (?,?)
              supertype:  relation_with_particular_mathematical_property (*)
                 supertype:  relation_with_particular_property (*)  this rather fuzzy type permits to group categorization schemes less common than those covered by the previous sibling categories
                    >part of:  relation__related_thing__relatedthing___related_with  type for any relation (unary, binary, ..., *-ary) and instance of pm#relation_type
        supertype:  symmetric_relation__symmetricrelation (?,?)  this category only serves structuration purposes: it is instance of pm#symmetric_relation_type which is not instance of pm#class_of_inheritable_relation_type
           supertype:  binary_relation_with_particular_mathematical_property (?,?)
        supertype:  transitive_relation (?,?)  this category only serves structuration purposes: it is instance of pm#transitive_relation_type which is not instance of pm#class_of_inheritable_relation_type
           supertype:  binary_relation_with_particular_mathematical_property (?,?)