Function pm#binary_function (?,? -> ?)  function that requires two arguments; currently not specialized by the  SUMO ternary relations since this seems useless (for now)
  type:  function_type  term-forming relation that maps from a n-tuple of arguments to a range and that associates this n-tuple with at most one range element; note that the range is a set_or_class, and each element of the range is an instance of the set_or_class
  type:  binary_function_type  class of functions requiring two arguments
  supertype:  ternary_relation__ternaryrelation__ternary_only_relation (?,?,?)  relation with a fixed arity equal to 3; specialized by the SUMO ternary relations not categorized elsewhere
     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