W3C home > Mailing lists > Public > public-rif-wg@w3.org > January 2007

Re: slotted notation -summary

From: Christian de Sainte Marie <csma@ilog.fr>
Date: Tue, 09 Jan 2007 16:12:16 +0100
Message-ID: <45A3B0D0.8090904@ilog.fr>
To: Michael Kifer <kifer@cs.sunysb.edu>
CC: "Public-Rif-Wg (E-mail)" <public-rif-wg@w3.org>

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 15:11:37 GMT

This archive was generated by hypermail 2.2.0+W3C-0.50 : Tuesday, 2 June 2009 18:33:35 GMT