Relation sumo#refers (?,?)  the 1st argument mentions or includes a reference to the 2nd argument, e.g., an article whose topic is a recent change in the price of oil may refer to many other things, e.g., the general state of the economy, the weather in California, the prospect of global warming, the options for alternative energy sources, the stock prices of various oil companies, etc.
  subtype:  sumo#names  sumo#represents  rdfs#see_also
  type:  pm#binary_predicate_type  the class of predicates relating two items - its valence is two
  supertype:  dc#Relation (?,?)  to specify a reference to a related resource; in WebKB, pm#relation or MORE PRECISE RELATION TYPES SHOULD BE USED INSTEAD
     supertype:  pm#binary_relation (?,?)  in WebKB, most relation types are binary and some have a variable number of arguments (as in KIF), hence this type is currently only specialized by types that I do not want to see as direct subtypes of pm#relation
        supertype:  pm#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:  pm#relation__related_thing__relatedthing___related_with  type for any relation (unary, binary, ..., *-ary) and instance of pm#relation_type