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Re: slotted notation -summary

From: Michael Kifer <kifer@cs.sunysb.edu>
Date: Tue, 09 Jan 2007 10:20:49 -0500
To: Christian de Sainte Marie <csma@ilog.fr>
Cc: "Public-Rif-Wg (E-mail)" <public-rif-wg@w3.org>
Message-ID: <14831.1168356049@cs.sunysb.edu>

No, I said just the opposite! What you want is wrong.

When I said "You want to map ..." you misunderstood me.
This expression was supposed to explain what you should really want, if you
saw the issue clearly.


> Michael,
> your reply confuses me; you seem to think that I propose to keep the OO 
> slotted notation and transform the expressions in relational slotetd 
> notation into OO slotted notation, whereas I am proposing the reverse.
> See details and, hopefully, clarifications below.
> Michael Kifer wrote:
> >>>We can distinguish at least 2 styles of slotted notation: relational and
> >>>object-oriented.
> >>
> >>At least for those two ones, isn't it the case that a slotted predicate 
> >>of the OO kind can always be represented as a conjunction of binary 
> >>slotted predicates of the relational variety, where the predicate 
> >>represents the slot/property/attribute, one of the roles is the object 
> >>(e.g., the first, by convention), and the other one is the value?
> > 
> > Relational slotted notation cannot be conveniently represented this way. In
> > Relational notation the Id of the object is implicit and cannot be
> > manipulated by the language.
> I apologize if I was not clear: all my email is about transforming 
> *from* OO slot notation *to* relational slotted notation. This requires 
> making the reference to the object explicit as one of the arguments of 
> each of the resulting binary predicates, indeed.
> > [...]
> >>
> >>So, why not have the closed relational slotted notation in RIF Core, and 
> >>some convention for transforming OO slotted predicated into that 
> >>notation (same kind of process as the one to bring an OSF term into its 
> >>solved form)? (*)
> > 
> > You want to map the relational slotted notation to the OO slotted notation
> > - not the other way around. Relational slotted notation implies that object
> > Ids are inaccessible, while OO notation assumes that they are. So, you can
> > map OO to relational slots in a certain sense.
> Hmmm... Isn't that what I am talking about? I propose that we consider 
> only the relational slotted notation for RIF Core, if needed; and that 
> we tranform, by convention, any expression in OO slotted notation into 
> conjunctions of binary relational predicates.
> My question whether this is always feasible can also be stated as: does 
> the OO slotted notation p(slot1->val1,...,slotn->valn) say anything 
> different than that the object p is in binary relation with (at least, 
> if we are in an open world) each of the values val1 to valn, binary 
> relations that we could name slot1 to slotn?
> > I am not sure that such a mapping makes good sense for our purposes. After
> > all, one can translate slotted notation into positional notation as well.
> > By this argument we can just leave positional stuff and nothing else.
> Right. Actually, I asked in another posting what was the motivation for 
> relational slotted notation. I can think of typing.
> > Yes. We can take the OO notation or leave both of them out for dialects.
> I meant: have the relational notation or leave both of them out.
> >>(**) 1) n-ary slotted predicate where the predicate is actually the 
> >>object;
> > 
> > In relational slotted notation the predicate is NOT an object, but a class.
> > (Please reread my comparison to get this cleared up.)
> Right. I understood that much. I was talking of OO slotted notation. 
> Sorry if it was not clear.
> Christian
Received on Tuesday, 9 January 2007 15:21:23 UTC

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