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cheating about reification

From: Sergey Melnik <melnik@db.stanford.edu>
Date: Wed, 24 Oct 2001 21:36:01 -0700
Message-ID: <3BD796B1.656A8878@db.stanford.edu>
To: Pat Hayes <phayes@ai.uwf.edu>, RDFCore WG <w3c-rdfcore-wg@w3.org>
Pat,

you pointed out many times that reification does not make sense. Of
course, there is no construct in the MT draft that allows to "access"
the reified statements directly. Hence, no resource symbols can ever be
associated with those reified "thingies". To me, this looks rather like
a problem in MT rather than a problem in Bill's or other people's
thinking.

In fact, all we have in the MT document that looks like a candidate
vehicle for dealing with reification is the IEXT mapping. However, as
you explained many times, IEXT maps resources to pairs of resources, and
thus is pretty much useless for reification.

What about the following addition to the MT. Let a ternary relationship
Reif be defined as:

1) IR x IR x (IR union LV) <= Reif
2) If (x,y,z) in (IR union Reif) x IR x (IR union LV union Reif),
   then (x,y,z) in Reif
3) Reif is the smallest set with (1), (2)

In other words, Reif contains all reified statements that can possibly
be constructed under a given interpretation I. Now we have some
"thingies" to reason about. By the way, it can be shown that the set
Reif indeed exists, but the proof is non-trivial.

Sergey
Received on Thursday, 25 October 2001 00:09:39 EDT

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