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Re: Outcomes from Jan 2 telecon

From: Michael Kifer <kifer@cs.sunysb.edu>
Date: Wed, 03 Jan 2007 07:04:14 -0500
To: Dave Reynolds <der@hplb.hpl.hp.com>
Cc: Chris Welty <cawelty@gmail.com>, "Public-Rif-Wg (E-mail)" <public-rif-wg@w3.org>
Message-ID: <8300.1167825854@cs.sunysb.edu>

> Chris Welty wrote:
> > 
> > 
> > Although we came to no resolutions today, I remain optimistic that we 
> > are close to having something for the RIF Core.  I want again to 
> > summarize what I think happened today to be sure I understood it, 
> > especially the cases where I thought there was agreement.
> > 
> > The main technical discussion at today's telecon centered again on the 
> > idea of "slots."
> > 
> > Harold agreed that the positional -> keyword mapping with predicate 
> > signatures would address his concerns.
> > 
> > Michael however pointed out that there are at least three semantics in 
> > use for "slots": relational, psi-terms, and the (nameless?) semantics 
> > used by F-Logic.  He is working on a document that clarifies what these 
> > semantics are, which will be out within the next day or so.
> > 
> > Hassan wasn't sure at first that this was any problem, suggesting that 
> > we keep one syntax and let the constraints carry these semantics. 
> > Several people felt that the differences should be reflected in the 
> > syntax as well, i.e. a different syntax for each "kind" of slot. Hassan 
> > disagreed, but Michael claimed to have some use cases from users of 
> > F-Logic that they might want a single rule set that supported more than 
> > one of these semantics.  Hassan then seemed to agree that if the 
> > different "kinds" of slots were to be mixed in a single ruleset, they 
> > should in fact be identified in syntax.
> Excellent summary up to that point.
> Then there was discussion on which, if any, of those three should go in 
> the core. Gerd suggested that rather than have all three in the core we 
> pick one based on use cases, I thought that received fairly broad agreement.
> [I was going to insert an appeal to the charter in here but the charter 
> isn't helpful. It says:
>     """In order to allow interoperability with RDF and object-oriented 
> systems, the syntax must support named arguments (also called "role" or 
> "slot" names), allowing n-ary facts, rules, and queries to be provided 
> through property/value interfaces."""
> Justifying slotted syntax based on RDF makes little sense to me but 
> presumably would correspond to the relational semantics, whereas 
> interoperability with object-oriented systems would presumably be better 
> served by one of the other semantics.]

Slots in RDF correspond not to relational semantics, but to F-logic semantics.


PS. I promised to send a summary about the different semantics for
    slots yesterday, but I am still communicating with Hassan on a few
    points to ensure accuracy.
Received on Wednesday, 3 January 2007 12:04:39 UTC

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