Relation pm#relation_from_binary_relation_type (binary_relation_type,*)
supertype: relation_from_relation_type
subtype: relation_to_another_binary_relation_type (binary_relation_type,binary_relation_type)
subtype: equivalent_property (binary_relation_type,binary_relation_type) in WebKB, use the link '='
subtype: sub_property_of (binary_relation_type,binary_relation_type) in WebKB, use the link '<'
subtype: inverse__reverse (binary_relation_type -> binary_relation_type) for inverseOf(R,S) read: R is the inverse of S; i.e. if R(x,y) then S(y,x) and vice versa; in WebKB, use the link '-'
subtype: domain (binary_relation_type,class)
subtype: range (binary_relation_type,class)