Meta-level requirements for RIF

[Francois Bry]

Dear All,

This is a try to clarify issues discussed today as well as again and
again in the past. In my opinion, we rurgently need an agreement on the
following:

1. Data (with their semantics) RIF is to access. In my opinion: RDF, XML
and OWL -- and I would stronlgy suggest Topic Maps as well.

2. What means "rule" for RIF. In my opinion, "deduction rules",
"normative ruyles" (aka integrity constraints), and "reactive rules" (or
ECA rules = Event-Condition-Action rules).
ECA rule include but are not limited to production rules. Events are
needed for an exchange of reactive behaviour between nodes in a
distributed context like the Web.

3. Semantics requirement for RIF: In my opinion, a declarative semantics
is needed in the first place but no procedural semantics. This would
leave interesting questions like termination (in certain cases) open. In
my opinion, many of these questions could be resolved without specifying
a full-fledged procedural semantics. And if some questions are left
open, the RIF would still be very usefull in practice.

François

[Sandro Hawke]

I think you meant to send this to public-rif-wg@..., Francois.

   -- Sandro

> Dear All,
>
> This is a try to clarify issues discussed today as well as again and
> again in the past. In my opinion, we rurgently need an agreement on the
> following:
>
> 1. Data (with their semantics) RIF is to access. In my opinion: RDF, XML
> and OWL -- and I would stronlgy suggest Topic Maps as well.
>
> 2. What means "rule" for RIF. In my opinion, "deduction rules",
> "normative ruyles" (aka integrity constraints), and "reactive rules" (or
> ECA rules = Event-Condition-Action rules).
> ECA rule include but are not limited to production rules. Events are
> needed for an exchange of reactive behaviour between nodes in a
> distributed context like the Web.
>
> 3. Semantics requirement for RIF: In my opinion, a declarative semantics
> is needed in the first place but no procedural semantics. This would
> leave interesting questions like termination (in certain cases) open. In
> my opinion, many of these questions could be resolved without specifying
> a full-fledged procedural semantics. And if some questions are left
> open, the RIF would still be very usefull in practice.
>
> François
>
>

[Adrian Walker]

Francois --

At 06:43 PM 4/18/2006 +0200, you wrote:
>Semantics requirement for RIF: In my opinion, a declarative semantics
>is needed

Agreed.

However, there is a problem.  W3C folks seem to lean strongly towards open
world, whereas database (and most other) folks mostly use closed world and
negation as failure.

In OW, if Adrian is not in the list of people who work for W3C, you cannot
conclude that Adrian does not work for W3C.  In CW you can.

                                  Cheers,



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[Francois Bry]

Adrian Walker wrote:

> Francois --
>
> At 06:43 PM 4/18/2006 +0200, you wrote:
>> Semantics requirement for RIF: In my opinion, a declarative semantics
>> is needed
>
> Agreed.
>
> However, there is a problem.  W3C folks seem to lean strongly towards
> open world, whereas database (and most other) folks mostly use closed
> world and negation as failure.
>
> In OW, if Adrian is not in the list of people who work for W3C, you
> cannot conclude that Adrian does not work for W3C.  In CW you can.
>

THis refers to nonmonotonic negation which is for the second phase.

If RIF is to be used with and as an extension to RDF, then "closed world
assumption" and "nonmonotonic negation" will be necessary -- whatebver
W3C folks lean strongly towards.

Francois