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Re: AW: AW: [PRD] Assert and AssertRetract test cases (ACTION-845)

From: Gary Hallmark <gary.hallmark@oracle.com>
Date: Tue, 21 Jul 2009 20:57:30 -0700
Message-ID: <4A668E2A.2030908@oracle.com>
To: Christian De Sainte Marie <csma@fr.ibm.com>
CC: Adrian Paschke <adrian.paschke@gmx.de>, Changhai Ke <changhai.ke@fr.ibm.com>, "'RIF'" <public-rif-wg@w3.org>
yes, csma and Changhai are correct. Adrian, I think the confusion is 
that ?X is bound to an oid, not a frame. This oid is just some Const. It 
has no meaning as an object unless it appears in the Member relation or 
the Frame relation, but it does not appear in either after a 
retract(?X), by definition.

Christian De Sainte Marie wrote:
>
> Adrian,
>
> Changhai is right, I think.
>
> "Adrian Paschke" <adrian.paschke@gmx.de> wrote on 21/07/2009 18:36:51:
> >
> > I would assume that the frame which is bound to variable ?X within
> > the atomic transaction of assert + retract is still bound to the
> > variable after the retraction, so it contains all previous
> > attributes of the frame and only the ex:discount attribute is changed.
>
> That is the case if you retract a frame, not if you retract the 
> object. The semantics of retracting the object is that you retract all 
> the known facts about it [1].
>
> In the end, only the facts that you asserted *after* the retract are 
> known, that is, in your example
>
> ex:john[ex:discount -> "0"] "
>
> > That is semantically an atomic assert+retract transaction is like a 
> modify.
>
> Again, Retract(frame)+Assert(frame_with_new_value) is equivalent to 
> Modify(frame_with_new_value), not 
> Retract(object)+Assert(frame_about_object_with_new_value)
>
> Christian
>
> [1] [w-alpha->w' if] α is Retract(o), where o is a constant, and /w' = 
> w \ {//o[s->v]// | for all the values of terms //s// and //v//} - 
> {//o#c// | for all the values of term //c//}/; (from 
> http://www.w3.org/TR/rif-prd/#Operational_semantics_of_atomic_actions)
>
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Received on Wednesday, 22 July 2009 03:58:22 GMT

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