- RDFS is useful, but does not solve all the issues
- Complex applications may want more possibilities:
						- can a program reason about some terms? E.g.:
								- “if «A» is left of «B» and «B» is left of «C», is «A» left of «C»?”
- obviously true for humans, not obvious for a program …
- … programs should be able to deduce such statements
 
- if somebody else defines a set of terms: are they the same?
								 - obvious issue in an international context
 
- 
              construct classes, not just name them
- restrict a property range when used for a specific class
            
- etc.