Ontolingua - Tips
It may appears that arity is handled inconsistently between relations and functions
- R(x,y) - R has arity 2
- F(x,y) - F has arity 3!
The term F(x,y) is equivalent to the predicate z=F(x,y), which can be written in relational form
- F(x,y,z) - F does have arity 3