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>

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 > 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 GMT

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