Given this, I feel that we should re-open Issue 473: https://cidoc-crm.org/Issue/ID-473-normal-custodian-of
If we cannot infer the current keeper, then nor can we infer the current normal/permanent keeper, despite what we concluded previously. Rob On Tue, Oct 18, 2022 at 3:57 PM Martin Doerr via Crm-sig < [email protected]> wrote: > Dear both, > > I think the discussion was that the "current" status cannot be inferred, > but it is based on a local "closed world" knowledge, and can only be "true" > until the time of the last respective update. So, I think the "no other > move" since time X, or "no other move without back move" since time X > exceeds the scope of logic. > Isn't it? > > I fear the "if and only if" statements are wrong anyway. Better you raise > an issue. I fear we have not understood circumstances that can lead to a > custody or loosing etc., including death, heirs etc. > > Best, > > Martin > > On 10/18/2022 7:44 PM, Christian-Emil Smith Ore via Crm-sig wrote: > > I tried to say that > > P55(x,y) ⇐ (∃z) [ [E9(z) ˄ P25i(x,z) ˄ P26(z,y)] > ˄ ¬ (∃w) [E9(w) ˄ P25i(x,w) ˄ P27(w,y)˄ > P182(z,w)]] > > > is not sufficient since the above implication is true if the premise is > false. So if there exist a newer move ( (∃w) [E9(w) ˄ P25i(x,w) ˄ > P27(w,y)˄ P182(z,w)]] is true) it is consistent with P55(x,y). The question > is what should the additional axiom be ? > The following is too strong since we do not require knowledge about a move > P55(x,y) ⇒ (∃z) [ [E9(z) ˄ P25i(x,z) ˄ P26(z,y)] > ˄ ¬ (∃w) [E9(w) ˄ P25i(x,w) ˄ P27(w,y)˄ > P182(z,w)]] > > That was what I thought. > Best, > Christian-Emil > ------------------------------ > *From:* Wolfgang Schmidle <[email protected]> > <[email protected]> > *Sent:* 18 October 2022 17:47 > *To:* Christian-Emil Smith Ore > *Cc:* [email protected] > *Subject:* Re: [Crm-sig] Deducing the current custody / ownership / > location > > Dear Christian-Emil, > > I am not sure I understand your additional axiom. How would it be > expressed in normal language? Are you saying "if the knowledge base knows > that x has current location y and that were was at least one Move of x, > then there must be a Move of x to y after which there is no more Move of x > away from y"? > > Best, > Wolfgang > > > > Am 17.10.2022 um 16:04 schrieb Christian-Emil Smith Ore via Crm-sig > <[email protected]> <[email protected]>: > > > > Dear Wolfgang, > > It is clear (at least to me) that the FOLs in the 'current' properties > are too weak. A complicating factor is that the FOL describes what we > explicitly know, that is, the status in the knowledge system. In a closed > world system, all shortcuts will imply at least one instance of the > corresponding long path. This is not the case in an open world view, I > think. > > > > P55(x,y) ⇐ (∃z) [ [E9(z) ˄ P25i(x,z) ˄ P26(z,y)] > > ˄ ¬ (∃w) [E9(w) ˄ P25i(x,w) ˄ P27(w,y)˄ > P182(z,w)]] > > > > If the premise in the FOL above is false, then P55(x,y) is trivially > true. This is ok if [E9(z) ˄ P25i(x,z) ˄ P26(z,y)] is false, but it is not > ok if > > (∃z) [ [E9(z) ˄ P25i(x,z) ˄ P26(z,y)] ˄ (∃w) [E9(w) ˄ P25i(x,w) ˄ > P27(w,y)˄ P182(z,w)]] > > is true. > > > > We need an additional axiom, something like > > (∃z) [P55(x,y) ˄ [E9(z) ˄ P25i(x,z) ˄ P26(z,y)] ⇒ ¬ (∃w) [E9(w) > ˄P25i(x,w) ˄ P27(w,y)˄ P182(z,w)]]] > > ? > > Best, > > Christian-Emil > > > > From: Crm-sig <[email protected]> > <[email protected]> on behalf of Wolfgang Schmidle via Crm-sig > <[email protected]> <[email protected]> > > Sent: 16 October 2022 14:37 > > To: [email protected] > > Subject: [Crm-sig] Deducing the current custody / ownership / location > > > > Dear All, > > > > I am trying to understand how one can infer the current custody / > ownership / location of a Physical Thing / Object. > > > > Let's assume that there has been a E10 Transfer of Custody / E8 > Acquisition / E9 Move to an Actor or Place y. If there was no later event > at all, it is inferred in the scope notes of P50 has current keeper / P52 > has current owner / P55 has current location that y is, in fact, the > current keeper / owner / location. For example, the scope note of "P52 has > current owner" says: "This property is a shortcut for the more detailed > path from E18 Physical Thing through P24i changed ownership through, E8 > Acquisition, P22 transferred title to to E39 Actor, if and only if this > acquisition event is the most recent." > > > > There is a stronger-sounding but actually weaker requirement that there > was no later event that included a "P28 custody surrendered by / P23 > transferred title from / P27 moved from" y. The owner / location scope > notes use the stronger requirement, the keeper scope note uses the weaker > requirement. It would be good to explain in the respective scope notes the > reasoning behind this difference. > > > > The FOL encodes the weaker requirement in all three cases. I assume the > discrepancy between scope notes and FOL is an oversight. (This was actually > my starting point.) > > > > The scope notes not only say "if" but "if and only if". Is there a way > to encode the "only if" part in FOL? This seems to be quite tricky. For > example, if there were three Moves: 1. from somewhere to A, 2. from A to B, > 3. from B back to A, then one can infer that A is the current location, but > only Move 3 (and not Move 1) is actually the long form of the shortcut "P55 > has current location". On the other hand, it does not follow from Move 1 > and 2 that A is not the current location. > > > > Should we worry about negative statements and incomplete knowledge in > our knowledge base? Or do we assume here that if there has been such an > event, then the knowledge base knows about it? (Or equivalently, if the > knowledge base does not know of any such event, then there was indeed > none?) Of course one can infer e.g. the current location based on a > possibly incomplete list of Moves in a given knowledge base, but whose > opinion would it represent? Can one still claim that the inferred statement > is the opinion of the knowledge base maintainers? > > > > In particular, what happens if an object disappears or gets destroyed? > One may infer the last keeper / owner / location before the destruction, > but both the scope notes and the FOL will happily argue that the destroyed > object nonetheless has a current owner / keeper / location. Perhaps the > destruction implies an implicit Transfer Of Custody where the custody has > been surrendered, but there is probably no implicit Acquisition or Move. > E64 End of Existence and E6 Destruction offer no concrete help, although > E64 says: "It may be used for temporal reasoning about things … ceasing to > exist". > > > > I assume this has already been discussed somewhere, but the discussion > didn't find its way into the scope notes. > > > > Best, > > Wolfgang > > > > > > _______________________________________________ > > Crm-sig mailing list > > [email protected] > > http://lists.ics.forth.gr/mailman/listinfo/crm-sig > > _______________________________________________ > > Crm-sig mailing list > > [email protected] > > http://lists.ics.forth.gr/mailman/listinfo/crm-sig > > > _______________________________________________ > Crm-sig mailing > [email protected]http://lists.ics.forth.gr/mailman/listinfo/crm-sig > > > > -- > ------------------------------------ > Dr. Martin Doerr > > Honorary Head of the > Center for Cultural Informatics > > Information Systems Laboratory > Institute of Computer Science > Foundation for Research and Technology - Hellas (FORTH) > > N.Plastira 100, Vassilika Vouton, > GR70013 Heraklion,Crete,Greece > > Vox:+30(2810)391625 > Email: [email protected] > Web-site: http://www.ics.forth.gr/isl > > _______________________________________________ > Crm-sig mailing list > [email protected] > http://lists.ics.forth.gr/mailman/listinfo/crm-sig > -- Rob Sanderson Director for Cultural Heritage Metadata Yale University
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