In the scope notes of the "current" properties it is written that,
say, P55 has current location, P55(x,y) is the case if and only if
the physical object x is not moved from the place y at a later date
than it was moved to y. Expressed in ordinary FOL (without any
requirement of open world this will be
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 is, P55(x,y) if and only if there exists a move z such that x
was moved to y in this move invent and it does not exist any other
move event moving x away from y where the move event z ended before
(or with) the start of the move event w. Under an open world view we
do not postulate the existence of such a z or require that the
knowledge base should contain information about such a (anonymous)
event. Therefore the equivalence is weakened to
P55(x,y) ⇐ (∃z) [ [E9(z) ˄ P25i(x,z) ˄ P26(z,y)] ˄ ¬ (∃w) [E9(w) ˄
P25i(x,w) ˄ P27(w,y)˄ P182(z,w)]]
postulating the existence of the shortcut if there exists a move z
such that x was moved to y in this move invent and it does not exist
any other move event moving x away from y where the move event z
ended before (or with) the start of the move event w.
This implication is true also in the case the premise is false, that
is, there exists a newer move event taking x away from y. Therefore
our knowledge base will be consistent even in this case which
contradicts the scopenote text. So that is why I suggested an
additional weaker axiom:
Ff the shortcut P55(x,y) exists and there is information about the
move event moving x to y, then there cannot be information about any
other move event moving x away from y at a later point in time.
May be I am wrong.
Best,
Christian-Emil
------------------------------------------------------------------------
*From:* Crm-sig <[email protected]> on behalf of Wolfgang
Schmidle via Crm-sig <[email protected]>
*Sent:* 19 October 2022 07:48
*To:* [email protected]
*Subject:* [Crm-sig] ISSUE: shortcuts in P50 has current keeper, P52
has current owner, P55 has current location
The shortcuts given in the scope notes / FOLs of P50 has current
keeper, P52 has current owner, P55 has current location are wrong. It
is unclear how to correct them, or if they can be corrected at all.
> Am 18.10.2022 um 21:55 schrieb Martin Doerr via Crm-sig
<[email protected]>:
>
> 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]>
>> 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]>:
>> >
>> > 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]> on behalf of
Wolfgang Schmidle via Crm-sig <[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
>> >
>> >
>> > _______________________________________________
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>>
>>
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>
>
> --
> ------------------------------------
> 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
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