comment on RIF

Dear all,

I am probably too late to comment but anyway, I try.

I read with interest the proposal
   http://www.w3.org/TR/rif-core

You specify that constants and variables are sorted.

I wonder how you define the sort/type of an object like 'bill'  who is 
an employee. Can the user define her own types like 'employee' within RIF?

Kind greetings, Manfred Jeusfeld, co-developer of ConceptBase