From: <jos.deroo.jd@belgium.agfa.com>

Date: Wed, 9 May 2001 16:45:32 +0100

To: aswartz@upclink.com

Cc: jos.deroo.jd@belgium.agfa.com, bwm@hplb.hpl.hp.com, martyn.horner@profium.com, w3c-rdfcore-wg@w3.org

Message-Id: <OF7750EEB7.0051048D-ON41256A47.003EE065@bayer-ag.com>

Date: Wed, 9 May 2001 16:45:32 +0100

To: aswartz@upclink.com

Cc: jos.deroo.jd@belgium.agfa.com, bwm@hplb.hpl.hp.com, martyn.horner@profium.com, w3c-rdfcore-wg@w3.org

Message-Id: <OF7750EEB7.0051048D-ON41256A47.003EE065@bayer-ag.com>

> > Two resources r1 and r2 can be mapped by D to the same entity. In that case > > we say they are equivalent. > > I think this is a mistake -- there are many pages which return the same > entity (the same set of text) but we cannot assume from this that they have > equivalent resources. To do so would be a grave mistake. > The entity returned may vary over time while the resource stays the same. > Just because at one point in time they return the same entity does not mean > that they always will. maybe not if we talk about set-of-entities which could go like: there is a set of resources called R there is a set of uris called U there is a function f:U->R for all u element of U there exists a r element of R such that f(u) = r (or we could represent a resource r as a skolem function of it's uri u) so u1 = u2 => f(u1) = f(u2) so u1 = u2 => r1 = r2 there is a set of set-of-entities called S (s element of S is meant to represent the possible states of a resource) there is a function g:R->S for all r element of R there exists a s element of S such that g(r) = s for all u element of U there exists a s element of S such that g(f(u)) = s so u1 = u2 => s1 = s2 -- Jos De Roo, AGFA http://www.agfa.com/w3c/jdroo/Received on Wednesday, 9 May 2001 10:48:22 EDT

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