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Re: regrets telecon on Tuesday

From: Hassan At-Kaci <hak@ilog.com>
Date: Mon, 21 Jan 2008 18:25:04 +0100
Message-ID: <4794D570.9070400@ilog.com>
To: axel@polleres.net
CC: Christian de Sainte Marie <csma@ilog.fr>, Jos de Bruijn <debruijn@inf.unibz.it>, RIF <public-rif-wg@w3.org>

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.

Sorry - you are right. I had misread your AND as the informal English 
"and". Jet-lagged I suppose... :-(


>> 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

Hassan At-Kaci  *  ILOG, Inc. - Product Division R&D
Received on Monday, 21 January 2008 17:26:12 UTC

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