- From: Pierre-Antoine Champin <pierre-antoine.champin@ercim.eu>
- Date: Wed, 15 Dec 2021 07:58:23 +0100
- To: Anthony Moretti <anthony.moretti@gmail.com>
- Cc: "public-rdf-star@w3.org" <public-rdf-star@w3.org>
- Message-ID: <d8c6bbe6-5934-b8b1-bdfa-989a6f133393@ercim.eu>
On 15/12/2021 05:45, Anthony Moretti wrote:
>
> 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.
>
>
> If I've found the right discussions you're right about it being a can
> of worms (169 <https://github.com/w3c/rdf-star/issues/169>, 170
> <https://github.com/w3c/rdf-star/issues/170>, 209
> <https://github.com/w3c/rdf-star/pull/209> etc). I read through them
> and still think that "occurrenceOf" is preferable to "realizationOf".
> After some thought, and also heeding Pat's advice about avoiding the
> use of "literal",
did I miss some message in the thread? Or are you referring to another
discussion with Pat?
> maybe the relations of concern could be:
>
> occurrenceOf (referentially transparent)
> mentionOf (referentially opaque)
I like that.
>
> In the dictionary, a "mention" is "a reference to someone or
> something". Every time I talk about a triple, whether in writing or
> speech, can be described as a mention of that triple.
>
> 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).
>
>
> There has been lots of discussion
> <https://lists.w3.org/Archives/Public/public-schemaorg/2018Jun/0013.html>
> (that I've been a part of) where people would like to broaden the
> scope of schema:Event to include such things as historical events and
> notable time periods. If schema:Event were to use the dictionary
> definition in its description ("a thing that happens or takes place,
> especially one of importance") then it might solve those problems and
> also be the domain for "occurrenceOf".
Good to know, thanks for the pointer.
>
> Regards
> Anthony
>
>
> On Wed, Dec 15, 2021 at 12:34 AM Pierre-Antoine Champin
> <pierre-antoine.champin@ercim.eu> wrote:
>
>
> 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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