- From: Jos de Bruijn <jos.debruijn@gmail.com>
- Date: Wed, 12 May 2010 14:17:09 +0200
- To: Axel Polleres <axel.polleres@deri.org>
- Cc: Christian De Sainte Marie <csma@fr.ibm.com>, Dave Reynolds <dave.e.reynolds@googlemail.com>, RIF <public-rif-wg@w3.org>
Going for 2 seems problematic, since it would mean Core is not a subset of PRD. However, if we would go for 2, I don't an issues with universal facts, since they are not allowed to have variables (by safeness [1]). In any case, let me repeat the wording I proposed that fits with option (1): * Equality terms and class membership terms *cannot* occur in universal facts, variable-free atomic formulas outside of rule premises, or rule conclusions -- they are allowed only in rule premises. The corresponding wording fitting for option (2): * Equality terms *cannot* occur in universal facts, variable-free atomic formulas outside of rule premises, or rule conclusions -- they are allowed only in rule premises. * Class membership terms *cannot* occur in rule conclusions -- they are allowed only in facts and rule premises. That said, I guess option (2) is a non-starter for most people, as it takes Core beyond PRD. Cheers, Jos [1] http://www.w3.org/2005/rules/wiki/Core#Safeness On Wed, May 12, 2010 at 1:59 PM, Axel Polleres <axel.polleres@deri.org> wrote: > > So, it seems we have two options: > > 1) rather painless, but contradicting the group's original resolution, i.e. > accept the rewording suggested by Jos [1] to clarify 2.3. > > 2) stick to the resoultion, by either adopting c) or d) from [2] (the resolution [3] is not clear about whether > universal facts should be allowed or not) and fix both 2.3 and the EBNF grammar. > > As I understand it, going for 1) needs at the very least a new group resolution that > overcomes the original resolution [3] (if that path is chosen, I would kindly ask to record my abstention) > > Axel > > 1. http://lists.w3.org/Archives/Public/public-rif-wg/2010May/0057.html > 2. http://lists.w3.org/Archives/Public/public-rif-wg/2010May/0052.html > 3. http://www.w3.org/2005/rules/wg/meeting/2009-01-15#resolution_3 > > On 12 May 2010, at 12:31, Christian De Sainte Marie wrote: > > > > > The resolution about membership in Core is recorded here: http://www.w3.org/2005/rules/wg/meeting/2009-01-15#resolution_3 > > > > It was, indeed, to allow membership in Core facts and conditions. > > > > Cheers, > > > > Christian > > > > IBM > > 9 rue de Verdun > > 94253 - Gentilly cedex - FRANCE > > Tel. +33 1 49 08 35 00 > > Fax +33 1 49 08 35 10 > > > > > > > > From: Dave Reynolds <dave.e.reynolds@googlemail.com> > > To: Jos de Bruijn <jos.debruijn@gmail.com> > > Cc: Axel Polleres <axel.polleres@deri.org>, Christian De Sainte Marie/France/IBM@IBMFR, RIF <public-rif-wg@w3.org> > > Date: 12/05/2010 12:09 > > Subject: Re: Urgent: Issue with RIF-Core EBNF Grammar? > > > > > > > > > > On 12/05/2010 09:36, Jos de Bruijn wrote: > > > Axel, Christian, all, > > > > > > I raised my concerns about the RIF-Core spec in a separate email. > > > > > > Concerning facts about class membership: they are both in BLD and PRD > > > (see [1]). > > > Concerning class membership atoms in rule conclusions: I do remember > > > that we explicitly forbade them in Core. > > > > That's my recollection too. > > > > Our official record of the decision [1] was to allow membership "in Core > > facts and conditions". > > > > We did at one point have an EBNF that reflected that resolution. > > > > My memory [2] was that Gary on behalf of the PRD group later pointed > > that asserting membership facts was just as problematic as concluding > > them via non ground rules. The problem being that in object-based PR > > implementations membership is hardwired in the external data model. So > > we decided to forbid any assertion of membership facts. I.e. the EBNF > > accurately reflects our intention[3]. > > > > The phrasing in section 2.3 is clarified by "they [equality terms and > > class membership terms] are only allowed in rule premises". I agree that > > the term rule "premise" is not defined in the document so it could be > > clearer but I don't see how one could reasonably interpret a ground fact > > as a "premise". So it seems to me the normative text and informative > > EBNF are in agreement. > > > > Dave > > > > [1] http://www.w3.org/2005/rules/wg/track/issues/48 > > [2] Which I've not been able to validate from the record trail. > > [3] That intention may be strange and hard to understand but that's the > > nature of working group compromises :) > > > > > > > > > > Sauf indication contraire ci-dessus:/ Unless stated otherwise above: > > Compagnie IBM France > > Siege Social : 17 avenue de l'Europe, 92275 Bois-Colombes Cedex > > RCS Nanterre 552 118 465 > > Forme Sociale : S.A.S. > > Capital Social : 611.451.766,20 € > > SIREN/SIRET : 552 118 465 03644 > > > -- Jos de Bruijn Web: http://www.debruijn.net/ LinkedIn: http://at.linkedin.com/in/josdebruijn
Received on Wednesday, 12 May 2010 12:18:07 UTC