Knowledge Systems Laboratory, Stanford
University
22
Comments on RDF and RDF-S
uSeverely lacking in expressive power
„Domain and range constraints rather than Value-Type
E.g., can’t define class of people all of whose children
are male
„No cardinality constraints
>Particularly
important for “exactly 1” and “at most 1”
„No decompositions
>Particularly
important for “disjoint” and “exhaustive”
„No axioms
„No negation (!)
uNot useful for checking consistency
E.g.,
can’t prove an object is not an instance of a class
uBasically a typing system
uDoes provide identifiers for objects
„Enables referencing and describing