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Re: regrets telecon on Tuesday

From: Axel Polleres <axel.polleres@deri.org>
Date: Tue, 22 Jan 2008 01:12:39 +0000
Message-ID: <47954307.3070608@deri.org>
To: RIF <public-rif-wg@w3.org>
CC: Christian de Sainte Marie <csma@ilog.fr>

Axel Polleres wrote:
> Hassan At-Kaci wrote:
>> Axel Polleres wrote:
>>> whereas, on the contrary in frames, any slot can appear 0 or several 
>>> times, i.e.
>>> person1[firstname -> "Christian", lastname -> "de Sainte Marie"]
>>> and
>>> person1[firstname -> "Christian"] AND person1[lastname -> "de Sainte 
>>> Marie"]
>>> say the exactly same thing, i.e. mutually entail each other.
>> What? You mean that there can be only one "person1" object named
>> "Christian"? 
> no, I mean whether I write the frame formula in version one or version 2 
> above, it is the same thing. that has nothing to do with keys. person1
> is the objectID ... maybe I should have written
> person1##person[firstname -> "Christian", lastname -> "de Sainte Marie"]
> and
> person1##person[firstname -> "Christian"] AND person1[lastname -> "de 
> Sainte
>  Marie"]
> to make this clearer.

p.s.: I meant, of course instance (#) not subclass (##), i.e.

person1#person[firstname -> "Christian", lastname -> "de Sainte Marie"]


person1#person[firstname -> "Christian"] AND
person1[lastname -> "de Sainte Marie"]


>> IMHO, what you are describing corresponds to the notion
>> of database record key(s) - i.e., the attribute(s) that characterize
>> individual records.
>> Furthermore, even if you do have a notion of keys (which we have
>> not discussed within RIF as far as I recall), there is still another
>> situation to take into consideration: just like algebraic (i.e.,
>> positional) terms are built of symbols that may have (or not)
>> well-formedness constraints (e.g., signatures, typing, annotations,
>> etc...). To make things even more interesting, not everyone agrees
>> with one specific semantics for the very same frame syntax (i.e., do
>> we allow repeated "slots" - and in this case, is this an error or is
>> it that such a slot has as value the set (or some kind of aggregate)
>> of all the values for this slot. Some also allow mandatory as well
>> as non-mandatory attributes - some even allow any symbol as a slot
>> (i.e., unconstrained signatures).
>> While the RIF BLD masterminds (i.e., the authors of the document:
>> Harold and Michael) give one possible semantics for these syntactic
>> constructs; but this semantics is not necessarily compatible with
>> many extant rule languages, several of which would wish to use the RIF.
>> -hak

Dr. Axel Polleres
email: axel@polleres.net  url: http://www.polleres.net/

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Received on Tuesday, 22 January 2008 01:12:52 GMT

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