RE: [RIF] homework for 10/17 telecon

> > As an example of typing in a rule condition language,
> > consider the following property atom in IRL:
> > 
> > 	cust:GoldCustomer; sCart:ShoppingCart(customer == cust);
> > 
> > It states that the customer property of the shopping cart sCart
> > has the value of cust, which is a varaible of type GoldCustomer.
> > It involves two variables, cust and sCart, both of which are
> > typed. Having a specific form, it should also be viewed as a
> > special type of atom, namely an object-valued property atom.
> > Rewritten in the current core condition language proposal as
> > the untyped standard predicate logic atom
> > 
> > 	customer( sCart, cust),
> 
> I would expect that sort of type stuff* to turn into additional
> premises.
> 
> In SPARQL[1], I might write
> 
> ... WHERE { ?cust a ex:GoldCustomer.
>   ?sCart a ex:ShoppingCart;
>     ex:customer ?cust }

Sure, you can map it in this way, but I don't see how you can 
reconstruct the typing information at the interchange destination 
side easily from such a reduced representation. How can you 
reconstruct, e.g., the destination SWRL atom

   customer( I-variable(sCart) I-variable(cust))

from the following concjunction of three atoms

   ShoppingCart( sCart) & Customer( cust) & customer( sCart, cust)

in a language where monadic predicates do not necessarily express 
types?

-Gerd

Received on Monday, 16 October 2006 18:40:56 UTC