W3C home > Mailing lists > Public > public-rif-wg@w3.org > May 2008

Re: adding existentials and conjunctions to BLD consequents

From: Gary Hallmark <gary.hallmark@oracle.com>
Date: Thu, 22 May 2008 07:47:40 -0700
Message-ID: <4835878C.2040009@oracle.com>
To: Sandro Hawke <sandro@w3.org>
CC: public-rif-wg@w3.org

I'm not sure about being in Core, but it would be really nice if the 
intersection of BLD and PRD allowed a consequent such as

Exists ?o (And(?o#T ?o[x->?x]))

My OBR->BLD translator approximates the Exists with the Skolem function 
rif:new(something-unique) and it does the And using two rules with 
identical conditions wrapped in a Group.

Sandro Hawke wrote:
> In planning to implement RIF for N3, the two extensions I mostly need
> are to allow existentials and conjunctions in the the rule consequents.
> These are straightforward extensions, with nice fallback rewrites, but I
> thought I would just raise the question of putting them directly in BLD.
> I note, in particular, that Production Rule systems want something very
> much like existentials in the consequent, too, so this might possibly
> even go into Core.  But maybe it's not exactly the same thing, and
> datalog certainly doesn't have it.
> I'm fine working with this as just an extension, but I thought I should
> at least raise the issue in case anyone else is sympathetic.
>      - Sandro
Received on Thursday, 22 May 2008 14:50:55 UTC

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