Dear Christian-Emil
I don't think that the axiom contradicts the scopenote text. In those
worlds where there is a move w taking x away from y and w is after z (so
the antecedent is false), P55(x,y) (the consequent) is false as well but
the axiom still holds.
Carlo
Il 19/10/22 13:23, Christian-Emil Smith Ore via Crm-sig ha scritto:
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 <crm-sig-boun...@ics.forth.gr> on behalf of Wolfgang
Schmidle via Crm-sig <crm-sig@ics.forth.gr>
*Sent:* 19 October 2022 07:48
*To:* crm-sig@ics.forth.gr
*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
<crm-sig@ics.forth.gr>:
>
> 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 <wolfgang.schmi...@uni-koeln.de>
>> Sent: 18 October 2022 17:47
>> To: Christian-Emil Smith Ore
>> Cc: crm-sig@ics.forth.gr
>> 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 <crm-sig@ics.forth.gr>:
>> >
>> > 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 <crm-sig-boun...@ics.forth.gr> on behalf of
Wolfgang Schmidle via Crm-sig <crm-sig@ics.forth.gr>
>> > Sent: 16 October 2022 14:37
>> > To: crm-sig@ics.forth.gr
>> > 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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>
> --
> ------------------------------------
> 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
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>
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