Response to AR3

Dear Alexandre,

Thanks for your continued support of RIF, and for the use cases in support of equality.

May we list your implementation on the RIF implementations page:

http://www.w3.org/2005/rules/wiki/Implementations

Alexandre Riazanov wrote:
> Hi everybody,
> 
> I am working on prototype for semantic querying of relational databases
> (http://www.freewebs.com/riazanov/query_answering.pdf),
> and RIF BLD is envisaged as one of the input languages (TPTP, OWL 2, SWRL
> and Derivational RuleML are the others).
> Since (a branch of) the Vampire prover is currently the core of the system,
> it will essentially become a rule engine for BLD, supporting query
> answering.
> 
> The first implementation will simply convert BLD to TPTP, so it will be
> useable with all TPTP reasoners.
> Since it's basically just a Java API, the toolkit may be useful for purposes
> other than TPTP conversion:
> it will have a factory for the abstract syntax + JAXB-based parser/renderer.
> 
> All the software will be open source. I am expecting to publish an alpha in
> September.
>  
> Since the positive equality in BLD is still in danger, I would like to
> mention a couple of
> examples I came across recently, working on the RDB stuff.
> 
> Use case 1. Semantic querying requires semantic mapping of RDB schemas,
> e.g.,
> by linking the tables to application domain concepts and relations.
> Typically,
> a part of a schema is just a declaration of functional dependencies between
> attributes
> of tables. These can be easily expressed if our language allows equality,
> e.g.
> the following rule states that the table_person.name functionally depends on
> table_person.sin :
> 
> ?NAME1 = ?NAME2
>    :-
> And
>   (
>       table_person(sin -> ?SIN, name -> ?NAME1),
>       table_person(sin -> ?SIN, name -> ?NAME2)
>    )
> 
> 
> Such rules can be used by the reasoner for search space reduction, e.g, by
> contextual rewriting.
> 
> 
> Use case 2. Suppose we use several RDBs designed by different people for
> different purposes.
> The same entities can be represented differently in different DBs. For
> example, the same
> person can be identified with his SIN in one DB, and with a surrogate
> integer key in another DB:
> 
> person_for_sin(?SIN) # Person
>     :-
> db1.table_person(sin -> ?SIN, name -> ?NAME)
> 
> 
> 
> person_for_key(?KEY) # Person
>     :-
> db2.table_person(key -> ?KEY, sin -> ?SIN, name -> ?NAME)
> 
> 
> hasSIN(person_for_key(?KEY),?SIN)
>     :-
> db2.table_person(key -> ?KEY, sin -> ?SIN, name -> ?NAME)
> 
> 
> 
> 
> So, for cross-querying we absolutely need something like this:
> 
> person_for_sin(?SIN) = ?P
>    :-
> And(
>         ?P # Person,
>         hasSIN(?P,?SIN)
>       )
> 
> 
> Please note that these are just recent examples that are fresh in my mind.
> I have seen others.