- From: Pierre-Antoine Champin <pierre-antoine.champin@ercim.eu>
- Date: Tue, 14 Dec 2021 15:04:15 +0100
- To: Anthony Moretti <anthony.moretti@gmail.com>
- Cc: "public-rdf-star@w3.org" <public-rdf-star@w3.org>
- Message-ID: <8980633d-fa46-0d57-2ee5-f910c2acecd3@ercim.eu>
On 14/12/2021 14:41, Anthony Moretti wrote:
>
> Exactly. What I like about the "realization" pattern (or any
> similar pattern involving quoted triples) is that it keeps a link
> between the complex construct (the event) and the simple triple
> (asserted or not).
>
> pa
>
>
> It's a good solution that preserves all the information.
>
> In place of "realizationOf" I'd like to suggest renaming it to
> "occurrenceOf". If we're discussing reoccurring relationships then
> each Event is an occurrence of that relationship.
>
> As a follow-on I'd also suggest renaming theexisting
> <https://w3c.github.io/rdf-star/cg-spec/editors_draft.html#occurrences>"occurrenceOf"
> relation to "literalOccurrenceOf" (and possibly renaming that section
> of the report to "Triples and literal occurrences of triples").
Note that the `:occurenceOf` predicate in the CG report is just an
*example*, it has no "official" standing in the CG report. Yes, I
avoided that term in order to avoid confusion with the discussion in the
report, but I do not consider any term as definitely taken. "occurrence"
vs. "literalOccurrence" would be fine by me, I guess.
Note however that we have tried, in the RDF-star group, to coin a
general vocabulary for occurrences... but we failed to reach consensus
after a long discussion, and decided to defer that to the future working
group. This is a nasty can of worms, with a lot of subtle distinctions.
So my proposal in this thread is something more targeted: a property
whose domain is restricted a given Event class (although, as Peter
Rivett poinrted out, schema:Event is maybe not the most appropriate one).
>
> Regards
> Anthony
>
>
> On Tue, Dec 14, 2021 at 6:45 PM Pierre-Antoine Champin
> <pierre-antoine.champin@ercim.eu> wrote:
>
>
> On 11/12/2021 05:33, Anthony Moretti wrote:
>>
>> Idea:
>>
>> define a schema:realizationOf property, whose domain is
>> schema:Event and range is rdf-star:Triple (with an inverse
>> property schema:realization). The above could be expressed in
>> JSON-LD-star [1] as follows:
>>
>> {
>> "@context": "https://schema.org/" <https://schema.org/>,
>> "@type": "Event",
>> "realizationOf": { "@id": {
>> "@id": "#bowls_club",
>> "captain": "#bob"
>> }},
>> "startDate": "01-01-2019",
>> "endDate": "31-12-2019"
>> }
>>
>> That works. Although when stating this I think the start and end
>> dates should also be in the RDF-star triple. If the dates aren't
>> there then the event is adding information to the triple, whereas
>> I think the intention of "realization of" is to show a one-to-one
>> mapping, is that right?
> no, see below
>> If the intention isn't a one-to-one mapping then it's sort of
>> saying "instance of", where the only thing differentiating
>> instances is the time period, which implies that all standard RDF
>> triples without start and end times are implicit *types* of
>> events (also makes sense to me).
>
> yes, this is the idea behind my examples.
>
> Note that, by design, RDF-star does not support the one-to-one
> mapping, because quoted triples are (roughly) like IRIs or
> literals: they represent the *same thing* everywhere they appear.
> This is discussed in the CG report [1].
>
>>
>> [
>> a :TenuredOfficeEvent ;
>> schema:name "Presidency of the United States"@en ;
>> :hasTermStartYear "1885"^^xsd:gYear ;
>> :hasTermEndYear "1889"^^xsd:gYear ;
>> :hasOfficer dbpedia:Grover_Cleveland
>> ] schema:author [
>> a schema:Person;
>> schema:worksFor
>> <https://www.whitehouse.gov/#this>
>> ] ;
>> schema:publisher <https://www.whitehouse.gov/#this> .
>>
>> [
>> a :TenuredOfficeEvent ;
>> schema:name "Presidency of the United States"@en ;
>> :hasTermStartYear "1893"^^xsd:gYear ;
>> :hasTermEndYear "1897"^^xsd:gYear ;
>> :hasOfficer dbpedia:Grover_Cleveland
>> ] schema:author [
>> a schema:Person;
>> schema:worksFor
>> <https://www.whitehouse.gov/#this>
>> ] ;
>> schema:publisher <https://www.whitehouse.gov/#this> .
>>
>> ## Turtle End ##
>>
>> Key point:
>>
>> No reification required, courtesy of RDF's fundamental essence :)
>>
>> Kingsley
>>
>>
>> That works, although it's less flexible because it interleaves
>> concepts. For it to be fully understood a reasoner has to
>> understand "Presidency of the United States" rather than simpler
>> concepts that can be reused like "is President of" and "United
>> States". Composition over inheritance
>> <https://en.wikipedia.org/wiki/Composition_over_inheritance> could
>> probably make the design simpler, but yeah it works for sure too.
>
> Exactly. What I like about the "realization" pattern (or any
> similar pattern involving quoted triples) is that it keeps a link
> between the complex construct (the event) and the simple triple
> (asserted or not).
>
> pa
>
> [1]
> https://w3c.github.io/rdf-star/cg-spec/editors_draft.html#occurrences
>
>>
>> Personally, modeling would be much cleaner and more complete if
>> all statements could have start and end time positions, and
>> ideally a location position, then every statement has the
>> _option_ of being scoped in space and time. The modeling of
>> recurring events then falls out of that and people could either
>> do it Kingsley's way with events or just use statements with
>> start and end times, whichever they prefer.
>
>
>>
>> Regards
>> Anthony
>>
>>
>> On Sat, Dec 11, 2021 at 3:43 AM Pierre-Antoine Champin
>> <pierre-antoine.champin@ercim.eu> wrote:
>>
>>
>> On 10/12/2021 04:05, Anthony Moretti wrote:
>>> Agreeing with Dan here, you could argue that any instance of
>>> schema:Event is also an example.
>> +1
>>>
>>> Taking Simon's example:
>>> Bob - is captain of - Bowls Club - Jan 1, 2019–Dec 31, 2019
>>> Bob - is captain of - Bowls Club - Jan 1, 2020–Dec 31, 2020
>>>
>>> Seems equivalent to:
>>>
>>> schema:Event
>>> Bob's captaincy of Bowls Club 2019
>>> startTime: Jan 1, 2019
>>> endTime: Dec 31, 2019
>>>
>>> schema:Event
>>> Bob's captaincyof Bowls Club 2020
>>> startTime: Jan 1, 2020
>>> endTime: Dec 31, 2020
>>
>> Idea:
>>
>> define a schema:realizationOf property, whose domain is
>> schema:Event and range is rdf-star:Triple (with an inverse
>> property schema:realization). The above could be expressed in
>> JSON-LD-star [1] as follows:
>>
>> {
>> "@context": "https://schema.org/" <https://schema.org/>,
>> "@type": "Event",
>> "realizationOf": { "@id": {
>> "@id": "#bowls_club",
>> "captain": "#bob"
>> }},
>> "startDate": "01-01-2019",
>> "endDate": "31-12-2019"
>> }
>>
>> (assuming that "realization" and "captain" are part of the
>> schema.org <http://schema.org> context)
>>
>> The annotation syntax could also be used, if bob was
>> *currently* captain of the club:
>>
>> {
>> "@context": "https://schema.org/" <https://schema.org/>,
>> "@id": "#bowls_club",
>> "captain": {
>> "@id": "#bob",
>> "@annotation": {
>> "realization": {
>> "@type": "Event",
>> "startDate": "01-01-2021",
>> "endDate": "31-12-2021"
>> }
>> }
>> }
>> }
>>
>> pa
>>
>> [1] https://json-ld.github.io/json-ld-star/
>>
>>
>> PS: in case anyone is wondering, the Turtle-star
>> corresponding to the above JSON-LD-star would be
>>
>> [] a s:Event ;
>> s:realizationOf << <#bowls_club> s:captain <#bob> >> ;
>> s:startDate "01-01-2019"^^s:Date ;
>> s:endDate "31-12-2019"^^s:Date.
>>
>> and
>>
>> <#bowls_club> s:captain <#bob> {|
>> s:realization [
>> a s:Event ;
>> s:startDate "01-01-2019"^^s:Date ;
>> s:endDate "31-12-2019"^^s:Date
>> ]
>> |}.
>>
>>>
>>> It seems natural to me that every triple should have start
>>> and end time positions and possibly also a location
>>> position. The above examples seem to me like different ways
>>> of saying the same thing, albeit the first has more
>>> structure. You could argue that schema:Event is just a
>>> convenience type for statements with temporal data.
>>>
>>> YAGO knowledge base is a good example:
>>> https://www.sciencedirect.com/science/article/pii/S0004370212000719
>>>
>>> Regards
>>> Anthony
>>>
>>>
>>> On Fri, Dec 10, 2021 at 8:20 AM Cox, Simon (L&W, Clayton)
>>> <Simon.Cox@csiro.au> wrote:
>>>
>>> Captain of the bowls club is another example.
>>>
>>> (I was in one of these the other day admiring the wooden
>>> honour boards – the same names come up repeatedly but
>>> not necessary sequentially.)
>>>
>>> *From:*Dan Brickley <danbri@google.com>
>>> *Sent:* Thursday, 9 December, 2021 22:57
>>> *To:* public-rdf-star@w3.org
>>> *Subject:* OnAgainOffAgain relations - beyond celeb
>>> marriage: Org membership
>>>
>>> The celebrity re-marriage example is interesting and
>>> real, but may look a bit artificial or cornercase. A
>>> similarly structured situation is much more common -
>>> membership of organizations.
>>>
>>> For example one organization being a member of another.
>>>
>>> https://www.wikidata.org/wiki/Q51698517 is the
>>> International Fact Checking Network (IFCN). It has a
>>> notion of membership grounded in review of members
>>> w.r.t. their official principles.
>>>
>>> Verified signatories are e.g.
>>> https://www.wikidata.org/wiki/Q30325238 (Full Fact).
>>> There are some organizations such as Snopes
>>> (https://www.wikidata.org/wiki/Q2287154) who were once
>>> members (verified signatories) but who are not currently.
>>>
>>> Wikidata uses annotations on a
>>> https://www.wikidata.org/wiki/Property:P463 edge between
>>> IFCN and Snopes to give start/end times (
>>>
>>> 15 April 2017, 5 June 2019). It also points to
>>> evidence/source document.
>>>
>>> As far as I know Snopes have only been members once, but
>>> if they were to rejoin it seems Wikidata could
>>> accomodate the task of representing this.
>>>
>>> Until I learn a better name for it that isn't too
>>> grandiose, I am calling these "on again, off again"
>>> relationships, in honour of the celebrity
>>> marriage/divorce usecase.
>>>
>>> Dan
>>>
>>> p.s. another example, not quite notable enough for
>>> Wikidata to record:
>>>
>>> I (https://www.wikidata.org/entity/Q56641640) have twice
>>> been a member of https://www.wikidata.org/wiki/Q7552326
>>> (AISB - Society for the Study of Artificial Intelligence
>>> and Simulation of Behaviour). But then I have multiple
>>> times lived in the U.K., or been in various restaurants;
>>> how do we scope RDF-Star's applicability? Which of these
>>> are reasonable places it could be used for time-scoped
>>> relationships?
>>>
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