Re: Three ideas

Hi Pat

Sure, and I have no problem with that. But(1) it must not be required for
> all RDF triples (quads, whatever), because many (most?) of them are not
> time-sensitive; and (2) the semantics of it should be made as sharply clear
> as possible, and should make sense. At some point, it should say what the
> conditions are for a sentence (in this new notation) to be true in an
> interpretation. And that is just plain TRUE, not contextually or
> universally or some other kind of quaifified or absolute or otherwise wierd
> 'truth'. I presume that these new kinds of interpretation will have some
> (mathematical model of) time built into them, of course, since now time has
> become part of the interpretation machinery of the very logic, rather than
> something to be described in an ontology.
>

Ok, this is great, I think we might actually be in alignment.

bio:JimmyCarter xx:USPresident "1977-1981"^^xsd:TimeInterval .


xx:USPresident rdf:type xx:TemporallyConstrainedRole .
> rdfs:Domain xx:USPresident xx:PresidentsOfUSA .
> xx:PresidentsOfUSA rdfs:subClassOf xx:USNativeCitizen .
> rdfs:Range xx:USPresident xsd:TImeInterval .


Yes that will definitely do. I appreciate you doing that, it looks
faultless, thank you.

Yes. Suppose we just say, add a timestamp and that's all. Presumably some
> timestamps are more exact that others (seconds versus calendar years, say).
> So we have one assertion stamped with 2022, another with 1642705241 Unix
> time. Are they at the same time? Does the first assertion hold at the
> second time (which is inside 2022) or not? This depends on whether a
> 'vague' timestamp means 'at some time in the interval' or 'at all times in
> the interval' or maybe something else, depending on what is being asserted.
> If we are goung to adopt a convention then we need to answer questions like
> this, and the answers have to work for all cases because it will then be
> baked into the formalism itself.


I absolutely agree, there should be no ambiguity. That's why I started
talking about inclusive-start and exclusive-end to describe the temporal
range, it looks like there have been some hard-learned lessons around this.
Even if nothing was to come of this discussion except for a recommendation
about the best way to describe a range (not just a temporal range) I think
that would be useful in itself.

The following point doesn't address the 2022 vs 1642705241 Unix time
question, but to do with 'at some time in the interval' vs 'at all times in
the interval', my view has always been that the easiest approach to reason
about and the one that scales is the latter, 'at all times in the interval'.

Regards
Anthony


On Fri, Jan 21, 2022 at 5:46 AM Patrick J. Hayes <phayes@ihmc.org> wrote:

>
>
> On Jan 19, 2022, at 11:28 PM, Anthony Moretti <anthony.moretti@gmail.com>
> wrote:
>
> Hi Pat
>
> I really appreciate the responses. I'm going to try to keep this as short
> as possible for everybody's benefit, if there's something that needs
> answering just call it out.
>
> If I'm meant to timestamp my graph, isn't that the same thing as saying it
>> has a temporal validity?
>>
>>  Yes, I agree that some widely recognized timestamping convention would
>> allow one to make assertions like this more safely. But note that "widely
>> recognized" (avoiding words like 'standard' and 'normative'). And relative
>> to your last point, then we would be taking the timestamp to be part of the
>> asserted sentence, in some way. And as I have explained in earlier posts,
>> once the time (and ony other 'contextual' parameters relevant to truth) is
>> included into the asserted sentence, that (larger) sentence is simply true.
>
>
> That's exactly what I thought I was suggesting with time and space
> positions though. Is there something subtle that I've missed? If a
> convention for timestamps at the graph level is ok then can't a convention
> be introduced at the statement level too?
>
>
> Sure, and I have no problem with that. But(1) it must not be required for
> all RDF triples (quads, whatever), because many (most?) of them are not
> time-sensitive; and (2) the semantics of it should be made as sharply clear
> as possible, and should make sense. At some point, it should say what the
> conditions are for a sentence (in this new notation) to be true in an
> interpretation. And that is just plain TRUE, not contextually or
> universally or some other kind of quaifified or absolute or otherwise wierd
> 'truth'. I presume that these new kinds of interpretation will have some
> (mathematical model of) time built into them, of course, since now time has
> become part of the interpretation machinery of the very logic, rather than
> something to be described in an ontology.
>
>
> I wouldn't have any problem with treating name changes as genuine changes
>> to the data rather than a time=related assertion, by the way.
>>
>
> I'm feeling a bit stupid because I really don't understand why the
> "presidentOf" and "name" statements are different.
>
>
> Well – and I am being purely pragmatic here – the former is inherently and
> widely understood to be time-constrained, to the point where a conversation
> like "Joe Soap was President" ="When?" is quite natural; whereas name
> changes are uncommon and when they happen to public figures, rare enough to
> be notable (c.f. The Artist formerly known as Prince, or Cassius
> Clay//Muhammed Ali).
>
> Why is the second one changing a "genuine change to the data" and the
> other not? Why are they different? Would you mind showing me the correct
> way to describe Biden as president?
>
>
> There is no "correct way", but my general rule would be, if the assertion
> clearly has an implicit "now", then it should include an explicit time in
> it. Things like being President are widely thought of as 'roles', so that
> the role exists timelessly but the person occupying it changes from time to
> time. Hence such cliche's as "The king is dead: long live the king." Then
> one way to write this in RDF would be to have an ontology of roles, so it
> might look like
>
> bio:JimmyCarter xx:USPresident "1977-1981"^^xsd:TimeInterval .
>
> (where I am assuming that XML schema gets to have a time-interval
> datatype, so replace this with some other way to trefer to the timeperiod
> if you prefer) and we also know, from an ontology called XX, things like
>
> xx:USPresident rdf:type xx:TemporallyConstrainedRole .
> rdfs:Domain xx:USPresident xx:PresidentsOfUSA .
> xx:PresidentsOfUSA rdfs:subClassOf xx:USNativeCitizen .
> rdfs:Range xx:USPresident xsd:TImeInterval .
>
> So that PresidentsOfUSA is an RDFS class of current and former US
> Presidents, connecting the time-linked property to the category of
> individuals.
>
> Would that do? Like any such convention, this requires of users of SPARQL
> to know enough about how things are represented to be able to write
> coherent queries. But that is always the case, however we choose to write
> things in RDF.
>
> I think Peter put it well when he said thinking about this stuff would rot
> your brain, my brain is definitely rotting right now haha.
>
> It would require a total rewrite of the RDF specs and coming to clear,
>> universally accepted, answers to a host of thorny questions.
>>
>
> That's a good enough answer to me I guess, but would it still be the case
> if it was just a "widely recognized timestamping convention" at the
> statement level?
>
>
> Yes. Suppose we just say, add a timestamp and that's all. Presumably some
> timestamps are more exact that others (seconds versus calendar years, say).
> So we have one assertion stamped with 2022, another with 1642705241 Unix
> time. Are they at the same time? Does the first assertion hold at the
> second time (which is inside 2022) or not? This depends on whether a
> 'vague' timestamp means 'at some time in the interval' or 'at all times in
> the interval' or maybe something else, depending on what is being asserted.
> If we are goung to adopt a convention then we need to answer questions like
> this, and the answers have to work for all cases because it will then be
> baked into the formalism itself.
>
> Pat
>
>
> Thanks for your time!
> Anthony
>
> On Thu, Jan 20, 2022 at 2:44 PM Patrick J. Hayes <phayes@ihmc.org> wrote:
>
>>
>>
>> On Jan 19, 2022, at 2:59 AM, Anthony Moretti <anthony.moretti@gmail.com>
>> wrote:
>>
>> Hi Pat! Thanks for joining the discussion!
>>
>> I honestly don't mind if all of the ideas I've put forward are wrong,
>> I'll drop them the second there's a convincing argument against them and be
>> happy to have learnt things in the process, it just doesn't seem like the
>> case yet. So, let's jump in!
>>
>> That the atomic number of sodium is 11 is simply true. It is not true "at
>> a time". To ask when it is true, or to try to give its truth some kind of
>> temporal scope or limit, is to commit a category error.
>>
>> This was the example we talked about in private, and I'll retype what I
>> said for the benefit of anybody who might be reading. In short I said: "Was
>> it true ten minutes ago? Yes. Is it true now? Yes.
>>
>>
>> It is just true. It is not true AT a time except in a sense which is
>> something like "If you were to ask me if this is true at time T, I would
>> say Yes." And of course that idea, of being assented to at a time, has a
>> temporal dimension. But that does not imply that the truth of the assertion
>> is in any way related to time. It is also true /wherever/ it is asserted.
>> Also at any height above sea level. Also /however/ it is said. If you
>> whisper "Atomic number of sodium is 11" softly it is true; and if you shout
>> it loudly it is true. Does this show that the truth of the proposition is
>> somehow relative to a range of ways it can be said out loud?
>>
>> Therefore even that relationship has an extent in time."
>>
>>
>> No, it doesn't show anything of the kind. If you believe that truth must
>> be truth at a time, then it might show that; but that obviously begs the
>> question.
>>
>>
>> On the Bette Davis example, maybe you can clarify something for me. Do
>> Tarskian truth conditions apply in RDF?
>>
>>
>> Yes, if I understand your question. LIke most logical semantic theories,
>> the RDF semantics is based on Tarskian model theory. Is that what you meant?
>>
>> Sincere question because I've assumed that recently, but I don't know for
>> sure. '"P" is true if, and only if, P'.
>>
>>
>> Um…yes, though of course RDF is not remotely expressive enough to state
>> the Tarski T sentence.
>>
>> Doesn't that imply bounds for temporal validity?
>>
>>
>> No, of course not. Where in that sentence do you see any reference to
>> time?
>>
>>
>> If I have this triple:
>>
>> :JoeBiden :presidentOf :UnitedStates
>>
>> Isn't that true only for a period of time?
>>
>>
>> In a tensed language, where assertions are made at times and we can use
>> 'now' and future and past tenses, yes. In a simple assertional logic (like
>> RDF, RDFS, OWL, FOL, HOL, …), no. Truth in such languages is not
>> relativized to times of assertion.
>>
>> By the way, even a tense logic would not be suitable for recording data.
>> The unmarked case in a tensed logic assertion, ie in the 'present tense'
>> without using past or future modalities, is asserted as being true "now".
>> But of course "now" when the data is recorded or published will not be
>> 'now' when it is used, later. So we would still need some way to record and
>> incorporate the time the assertion is intended to be about, expressed in
>> some untensed way.
>>
>> Are we meant to avoid saying things like that?
>>
>>
>> I wish people would not (though it is more acceptable if it is clearly
>> asserted inside some context with a universally understood date/time
>> marker. See below.)
>>
>> What about:
>>
>> :JoeBiden :name "Joe Biden"
>>
>> He could change his name in the future. It's becoming a bit unclear to me
>> what I'm allowed to say in RDF or when I'm allowed to say them.
>>
>>
>> First, you are ALLOWED to do whatever you want. The issue is, will other
>> users be able to understand your meaning wihtout getting confused? Where
>> "users" include RDF-valid inference engines which might use your RDF
>> together with RDF written by others who might be expressing themselves with
>> more precision.
>>
>> I wouldn't have any problem with treating name changes as genuine changes
>> to the data rather than a time=related assertion, by the way.
>>
>> If I'm meant to timestamp my graph, isn't that the same thing as saying
>> it has a temporal validity?
>>
>>
>> Yes, I agree that some widely recognized timestamping convention would
>> allow one to make assertions like this more safely. But note that "widely
>> recognized" (avoiding words like 'standard' and 'normative'). And relative
>> to your last point, then we would be taking the timestamp to be part of the
>> asserted sentence, in some way. And as I have explained in earlier posts,
>> once the time (and ony other 'contextual' parameters relevant to truth) is
>> included into the asserted sentence, that (larger) sentence is simply true.
>>
>>
>> And even in a tensed language, we *can* speak of the future. We can even
>> speak of futures that we believe will not exist: this happens all the time
>> in planning, for example, where a reasoner might decide to not do something
>> because it forsees that if it does do it, bad things will happen. So the
>> present cannot be a bound. So what is the bound?
>>
>>
>> Yes, I agree we can speak about the future, I made that point earlier in
>> the thread. We can describe future events in the same way that we can
>> describe fictional things.But those statements won't be true in a Tarskian
>> sense until those futures eventuate
>>
>>
>> No, sorry, this is nonsense, and it has nothing to do with Tarski. Look,
>> you just contradicted yourself. We "describe" future events by asserting
>> sentences (or maybe propositions) about them. If these sentences are not
>> (claimed to be) true, then we have not made any assertions at all.
>> To describe IS to claim truth.
>>
>> , hence the present being an upper bound.
>>
>> I wonder, do you realize that you are not just arguing with RDF here, but
>> with close to 1.5 centuries of formal philosophy of logic? Ever since Prior
>> first described tense as a modality, tensed modal logics have been a clear
>> subfield, but AFAIK nobody has concluded that all of logic must be tensed
>> (still less spatially situated), or that the notion of truth is itself
>> inherently temporal in nature.
>>
>>
>> I just did a quick google of these things
>>
>>
>> Oh, come on. You did a "quick google" of over a century of literature in
>> a field of precise philosophy, much of it using fairly heavy mathematics,
>> and that justifies a (false) conclusion?
>>
>> The Stanford Encyclopedia of Philosophy (widely taken as authoritative)
>> has a main article on 'Truth', which says
>>  ".. for this discussion, sentences are fully interpreted sentences,
>> having meanings. We will also assume that the sentences in question do not
>> change their content across occasions of use, i.e., that they display no
>> context-dependence. We are taking sentences to be what Quine (1960) calls
>> ‘eternal sentences’."
>> The article does not even mention any notion of truth relativized to
>> times or other contexts or parameters.
>>
>> and it looks like an ongoing debate between tensed and tenseless theories
>> of time,
>>
>>
>> and some people arguing that both are valid.
>>
>>
>> Valid? Of course tensed languages exist and are coherent. Modal tense
>> logics have a very elegant semantics, courtesy of Kripke, and have been
>> very thoroughly studied. My point is not that they are somehow 'invalid",
>> but that RDF is not one of them. And I assure you that if it were, its
>> semantics would look very different than it now does.
>>
>> If that's so, does it hurt to add optional time and space positions like
>> I'm suggesting?
>>
>>
>> It would require a total rewrite of the RDF specs and coming to clear,
>> universally accepted, answers to a host of thorny questions. For a start,
>> what structure do we presume time to have? (A line? Branching futures, so a
>> tree? Or a forest?) DIfferent answers yield different notions of
>> validity for tensed sentences.
>>
>> But in any case, adding tenses doesn't help, as noted earlier.
>>
>> Pat
>>
>> It feels intuitive
>>
>> , and I see it as a solution to a lot of modeling problems.
>>
>> Regards
>> Anthony
>>
>>
>> On Wed, Jan 19, 2022 at 5:17 PM Patrick J. Hayes <phayes@ihmc.org> wrote:
>>
>>
>> On Jan 17, 2022, at 8:02 PM, Anthony Moretti <anthony.moretti@gmail.com>
>> wrote:
>>
>> If anybody isn't following Pierre-Antoine and me, I'll try to give a
>> summary of what I think the problem might be, and I'll follow it with an
>> example. There's an example in my last email too, Obama's first term as
>> president.
>>
>> In typical modeling, events have an ID and you can use that ID to find
>> statements about the start and end time of the event. If you have
>> reoccurring events, like the celebrity marriage example, there's no problem
>> because each event is uniquely identified.
>>
>> In RDF-Star, people are creating events by annotating triples with start
>> and end times, and often there are accompanying annotations. If there's a
>> reoccurring event, or if the annotations are only about a specific part of
>> an event, when you do the expansions you no longer know which event the
>> accompanying annotations are about because there are no event IDs and
>> the core triples being used as the subject of those annotations are
>> identical.
>>
>> In my view the problem isn't with RDF-Star it's with RDF. I think the
>> basic unit of description, the triple, is missing components. Every triple
>> describes a relationship and every relationship has an extent in time.
>>
>>
>> Wrong.
>>
>> Things can't be in a relationship if they don't exist yet
>>
>>
>> Wrong
>>
>> , and the future is yet to happen, those two things mean that every
>> relationship is implicitly lower-bounded by the existence of the things
>> being described
>>
>>
>> Wrong
>>
>> , and implicitly upper-bounded by the present.
>>
>>
>> No, that is all completely mistaken. Relations as such have nothing
>> whatever to do with time – unless, of course, they are relations between
>> times or other temporal things. And a fact represented by an assertion
>> (such as an RDF triple) of a relation holding between things need not  be
>> inherently temporal in any way. That the atomic number of sodium is 11 is
>> simply true. It is not true "at a time". To ask when it is true, or to try
>> to give its truth some kind of temporal scope or limit, is to commit a
>> category error.
>>
>> This is, or should be, simply obvious for facts about mathematics or
>> scientific physical data, but it also true of many of the everyday
>> asssertions found in ordinary prose. Take for example this, from a
>> Wikipedia biography: "<Bette Davis> had her critical breakthrough playing a
>> vulgar waitress in Of Human Bondage (1934) although, contentiously, she was
>> not among the three nominees for the Academy Award for Best Actress that
>> year." That sentences contains several linked assertions which are (I
>> presume) true. But they are not true at any particular time. That Bette
>> Davis played the part of a vulgar waitress in the move 'Of Human Bondage'
>> in 1934 is TRUE. It is not true-now or true-after-1934 or -after-(5 April
>> 1908). It is a simple fact.
>>
>> Now, you might object that it wasn't true in, say, 1921 (because it
>> hadn't happened yet) or 1847 (because Bette Davis didn't exist then), but
>> all such claims commit the same mistake, of taking truth to be something
>> with a tense. Supose (perhaps at a seance) someone in 1847 had spoken this
>> sentence, perhaps in a trance, and it had been carefully recorded at the
>> time and then a historian in 1953 had found this record, would people say,
>> Wow, what an amazing prediction? Or would they say, So what, it wasn't true
>> in 1847, so it wasn't a prediction at all? Your rule would require the
>> latter.
>>
>> Even if one takes the view (which I think you do) that all truth claims
>> are tensed, time-relative, and the apparent timelessness of mathematical or
>> scientific facts merely hides an implicit universal quantification, so that
>> one should understand "the atomic number of sodium is 11" to be shorthand
>> for "at all times T, the atomic number of sodium is 11 at time T"; even
>> then, that Bette Davis played the part of a vulgar waitress in the move 'Of
>> Human Bondage' in 1934, was just as true in 1847 as it is now. Of course,
>> nobody knew it was true then, and certainly nobody had any kind of
>> epistemic licence to assert it back then; but it was true. That sentence is
>> not in any way indexical, so its truth does not depend on when it was
>> asserted (unlke, say "Bette Davis will appear in a movie 89 years from
>> now"), so if it is true when asserted in 1934 or 2021, then it is equally
>> true when asserted in 1847 or indeed any other date. Our ignorance of a
>> fact does not make that fact any less true.
>>
>> And even in a tensed language, we *can* speak of the future. We can even
>> speak of futures that we believe will not exist: this happens all the time
>> in planning, for example, where a reasoner might decide to not do something
>> because it forsees that if it does do it, bad things will happen. So the
>> present cannot be a bound. So what is the bound?
>>
>> Some relationships have narrower extents in time than those two bounds,
>> and some relationships have multiple discontinuous extents in time, but
>> there's no place in a triple to describe those. Why? A similar idea applies
>> to space, some relationships are only true in specific regions of space.
>>
>>
>> I wonder, do you realize that you are not just arguing with RDF here, but
>> with close to 1.5 centuries of formal philosophy of logic? Ever since Prior
>> first described tense as a modality, tensed modal logics have been a clear
>> subfield, but AFAIK nobody has concluded that all of logic must be tensed
>> (still less spatially situated), or that the notion of truth is itself
>> inherently temporal in nature.
>>
>>
>> I believe a fix for this
>>
>>
>> As the proverb says, if it ain't broken, don't fix it.
>>
>> Pat
>>
>> would be optional time and space positions that can be left blank if not
>> required:
>>
>>     Subject Relation Object T1 T2 SpatialBound
>>
>> With that, event ambiguity is resolved without the need for event IDs.
>>
>> I'll go into it in another email, but the temporal range should ideally
>> be inclusive-start and exclusive-end, so some of my earlier examples
>> actually need correction around that.
>>
>> Here's a more complex example that involves both time and space and
>> builds on an example I gave at the beginning of the thread:
>>
>> Using existing RDF-Star, and mimicking how others appear to be using it:
>>
>> :BigMac :price-USD 5.66
>>     {|
>>         :quantitySold 550000000
>>         :statedIn :Wikipedia
>>         :region :UnitedStates
>>         :startTime 2021
>>         :endTime 2022
>>     |}
>>
>> Which expands to:
>>
>> :BigMac :price-USD 5.66
>> << :BigMac :price-USD 5.66 >> :quantitySold 550000000
>> << :BigMac :price-USD 5.66 >> :statedIn :Wikipedia
>> << :BigMac :price-USD 5.66 >> :region :UnitedStates
>> << :BigMac :price-USD 5.66 >> :startTime 2021
>> << :BigMac :price-USD 5.66 >> :endTime 2022
>>
>> There's so much ambiguity in both of the above. If the original intention
>> was to describe the quantity sold in that specific region during that
>> specific time then I think the expansion breaks that, or at the very least
>> leaves it open to be broken by further statements if the price ever happens
>> to be the same in a different period of time or a different region. Also,
>> if the original intention was to say that all of the information was stated
>> in Wikipedia, then I think the expansion breaks that too.
>>
>> A better way might be to use optional time and space positions and a
>> "complex statement", which handily also results in metadata being separated
>> from additional data:
>>
>> :BigMac :price-USD 5.66 2021 2022 :UnitedStates
>>     { :quantitySold 550000000 }
>>     {| :statedIn :Wikipedia |}
>>
>> Which expands to:
>>
>> :BigMac :price-USD 5.66 2021 2022 :UnitedStates
>> { :BigMac :price-USD 5.66 2021 2022 :UnitedStates } :quantitySold
>> 550000000
>> << :BigMac :price-USD 5.66 2021 2022 :UnitedStates >> :statedIn :Wikipedia
>> << { :BigMac :price-USD 5.66 2021 2022 :UnitedStates } :quantitySold
>> 550000000 >> statedIn :Wikipedia
>>
>> Even though this is a complex example, I think the time/space ambiguity
>> and metadata ambiguity are both gone now.
>>
>> In summary, I feel like time and space positions should exist in RDF and
>> it would fix some of the problems in RDF-Star too.
>>
>> Regards
>> Anthony
>>
>>
>> On Sat, Jan 15, 2022 at 1:48 PM Anthony Moretti <
>> anthony.moretti@gmail.com> wrote:
>> I see your point, and I believe that's a valid approach. But I am not
>> sure everyone wants to commit to that kind of ontological detail. As I
>> wrote in my previous mail: conflating past and future event into the same
>> class works well for many practical use cases.
>>
>> I agree. And, as Pete described, if the classification is important to a
>> reasoner it can be done by the reasoner anyway. My point was just to say
>> that implicit temporal bounds still seem to exist even for that very
>> difficult example, and, by doing that, I was trying to chop away at reasons
>> for not having optional time and space positions.
>>
>> In fact, optional time and space positions might actually help when
>> describing future events because they let you easily set expiry dates for
>> the things you say. For example, if you were planning WebConf2022 and the
>> dates for it were still changing you could release a statement that was
>> valid for only a certain period of time:
>>
>> :WebConf2022 :startDate "2022-04-25"^^xsd:date 2022-01-15 2022-01-21
>>
>> And then if plans change the following week and the event gets pushed
>> back a month, which is happening a lot right now for in-person events (I
>> know WebConf2022 is online), you could release an updated statement that
>> was valid for a new period of time:
>>
>> :WebConf2022 :startDate "2022-05-23"^^xsd:date 2022-01-22 2022-01-28
>>
>> Aside from modeling simplicity, I think the other major argument for time
>> and space positions is that order of assertion matters.
>>
>> ??
>>
>> Not in RDF, it does not.
>>
>>
>> I don't want to say I'm certain of this, but I think for triples that are
>> time/space dependent and then used as the subject or object of another
>> statement (in plain RDF via the use of identifiers) it does seem to matter.
>> The triple needs to be completed first for further statements to make
>> sense, and I think RDF-Star exposes the problem. If that's not the case can
>> someone please give me a counterexample?
>>
>> The "Thomas traveling to Paris" example is a modification of an example
>> Thomas gave in a different thread, and I'm dropping it because, as Pete
>> also notices, it has various issues. The following example (Obama's first
>> term in office) is an example I'm creating myself, but I'm sure people are
>> going to try and do stuff like this because it's already happening with
>> the celebrity marriage example:
>>
>> :BarackObama :presidentOf :UnitedStates
>>     {|
>>         :statedIn :Wikipedia
>>         :startTime 2009
>>         :endTime 2013
>>     |}
>>
>> What was stated in Wikipedia? The incomplete triple or the one completed
>> by the temporal constraints? I think what is meant is the following, with
>> the temporal constraints stated first and as additional data rather than
>> metadata:
>>
>> :BarackObama :presidentOf :UnitedStates
>>     {
>>         :startTime 2009
>>         :endTime 2013
>>     }
>>     {| :statedIn :Wikipedia |}
>>
>> Even if the above format were available, people would probably still try
>> to do something like:
>>
>> :BarackObama :presidentOf :UnitedStates
>>     {
>>         :secretaryOfState :HillaryClinton
>>         :startTime 2009
>>         :endTime 2013
>>     }
>>     {| :statedIn :Wikipedia |}
>>
>> But if the temporal constraints aren't asserted first you have a similar
>> issue upon expansion because HillaryClinton wasn't Secretary of State for
>> his entire presidency, only for his first term.
>>
>> Having optional time and space positions makes the order of assertion
>> clear and the time-dependent triple is completed first before further
>> statements are made. Separating additional data from metadata does the same
>> thing and clarifies what the metadata is about:
>>
>> :BarackObama :presidentOf :UnitedStates 2009 2013
>>     { :secretaryOfState :HillaryClinton }
>>     {| :statedIn :Wikipedia |}
>>
>> RDF(-star) has no such notion. Assuming that what you wrote above is
>> supposed to be RDF-star (replacing curly brackets with double angle
>> brackets), then the semantics of RDF-star (directly inherited from RDF)
>> requires that all four statements are interpretable independently of each
>> other, and are all considered true (assuming that you "trust"/"accept" the
>> whole graph as true).
>>
>> So I guess what I'm saying is that some triples, time/space dependent
>> ones, don't stand on their own and can't be considered true or false, and
>> instead of telling people to avoid them, or telling people to avoid forms
>> like the above whose expansion will include incomplete triples, let's
>> embrace them and design a solution for them. Bonus points that it's a
>> super simple way to model things so it's great for beginners, bonus points
>> that it also handles reoccurring events, bonus points that it solves for
>> our other dimension, space, at the same time.
>>
>> To answer this question, we need to precisely specify the meaning of each
>> term of the used ontology. Since this is your example, I would expect you
>> to know... :-)
>>
>> The original example is Thomas', but aside from that, if there's
>> ambiguity due to the chosen tense for the relation, which ideally shouldn't
>> be a factor, then a lot of that goes away when you have valid times and can
>> then opt for, say, present tense all of the time and have everything still
>> be clear. The point I was trying to make though was that the triples
>> were examples of the above, incomplete triples that need time/space
>> information to complete them.
>>
>> But more importantly, I reiterate my request to be explicit about what
>> you mean when you write "statement". Each RDF triple makes a statement,
>> that IS either true or false. However, a given set of RDF triples might
>> give an description of something else (e.g. an anthony-statement) that
>> might be deemed *incomplete* for some uses.
>>
>> Once we have a clear distinction between rdf-statement and
>> anthony-statement, then we can discuss whether a given set of
>> rdf-statements provides a complete and accurate description of a given
>> anthony-statement.
>>
>>
>> I'm still not clear what you mean by this, but I'll try to understand. Of
>> the four statement types I proposed the closest to an RDF triple is a
>> "Simple statement", which ideally would just be an RDF triple with optional
>> time and space positions and the ability to have any type of statement as
>> subject or object. A given set of simple statements, which would
>> be provided using a compound statement that also has optional time and
>> space positions, could then provide a complete and accurate description of
>> any of the other statement types. Is that an answer to your question? Sorry
>> if I've still misunderstood.
>>
>> Regards
>> Anthony
>>
>> On Sat, Jan 15, 2022 at 2:26 AM Pete Rivett <pete.rivett@agnos.ai> wrote:
>> I'd still take a modeling approach rather than ad hoc use of rdf-star
>> annotations (which, as I pointed out in my last email, we have no way of
>> documenting a schema for).
>>
>> From a modeling point of view I'd argue:
>> a) for modeling WebConf2022 as a simple Event. You could additionally and
>> dynamically add the class FutureEvent using the restriction :startTime >
>> now(). And, indeed PastEvent where :endTime < now().
>> if needed you could have an additional property :status with values
>> appropriate to your interest in its lifecycle such as :Conceived,
>> :Resourced, :Committed, :Announced, :Started, :Completed,
>> :ProceedingsPublished.
>>
>> b) if you're interested in multiple journeys why not actually model them:
>>  _journey1 a :Journey ;
>>   :traveler :Thomas ;
>>   :destination :Paris ;
>>   :timing [a :Period;
>>       :start T1 ;
>>       :end :T2
>>   ]
>> (you probably want an :origin place too)
>>
>> Generally I'd caution against trying to use Fictional: it becomes very
>> subjective. For example is Klingon
>> https://en.wikipedia.org/wiki/Klingon_language a fictional language?
>> It originated in a fictional TV series but it has real speakers, works of
>> literature and a language institute. And an official ISO language code
>> (@tlh). If Klingon is fictional then why is Esperanto not?
>>
>> Pete
>>
>> On Thu, 13 Jan 2022 at 18:40, Anthony Moretti <anthony.moretti@gmail.com>
>> wrote:
>> Earlier Pierre-Antoine wrote:
>>
>> Ok, let's take another example:
>>
>> :theWebConf2022 a s:Event ;
>>     s:startDate "2022-04-25"^^xsd:date ;
>>     s:endDate "2022-04-29"^^xsd:date .
>>
>> would you consider that those triple will only be valid on 2022-04-25? Or
>> would you argue that this event already exists, even though it has not
>> occurred yet?
>>
>>
>> This is a great discussion because I don't think time has been given the
>> attention it deserves. The following are my current thoughts, I'm happy to
>> hear more opinions though.
>>
>> There's a saying "the future is fiction until it happens". We can
>> definitely talk about fictional things, Fabio gives the example of Mickey
>> Mouse but you can even include abstract things like numbers, they're mental
>> concepts and I'd argue that the concepts exist from the moment they're
>> imagined. We can talk about fictional things without problem as long as
>> it's understood that they're fictional, this can be explicit by
>> saying Mickey Mouse is a FictionalCharacter, or implicit when talking about
>> abstract things like numbers. You could create a hierarchy for fictional
>> things by duplicating schema-org and prefixing all of the class names with
>> "Fictional":
>>
>> Thing
>>     Person
>>     Place
>>     Event
>>
>> FictionalThing
>>     FictionalPerson
>>     FictionalPlace
>>     FictionalEvent
>>
>> I'd argue that past events belong in the first hierarchy and future
>> events belong in the second, like so:
>>
>> FictionalThing
>>     FictionalEvent
>>         FutureEvent
>>
>> Pat mentioned Tarskian truth conditions, and I think the WebConf2022
>> example fails that, even though it's convenient to describe it like that
>> because it matches how you'd describe past WebConfs. It might be more
>> accurate to say:
>>
>> :WebConf2021 a :Event
>>     :startDate 2021-04-19
>>     :endDate 2021-04-23
>>
>> :WebConf2022 a :FutureEvent
>>     :scheduledStartDate 2022-04-25
>>     :scheduledEndDate 2022-04-29
>>
>> And only once the event has happened, and a reality has occurred that can
>> be described, describe it in the first manner like WebConf2021.
>>
>> Like I said, I'm happy to hear more opinions on all of this though.
>>
>> So I am still not convinced that triples are the right level of
>> granularity for systematically attaching contextual metadata. Following
>> Pat, I prefer to keep rdf-statements dead-simple (1), and model more
>> complex things (like anthony-statements) with a bunch of triples.
>>
>> Aside from modeling simplicity, I think the other major argument for time
>> and space positions is that order of assertion matters. If people annotate
>> with start and end times, which they're already doing, then expansions
>> don't work correctly. Going with an earlier example:
>>
>> :Thomas :travelingTo :Paris
>>     {
>>         :by :Train,
>>         :startTime T1,
>>         :endTime T2,
>>     }
>>
>> Would expand to:
>>
>> :Thomas :travelingTo :Paris
>> { :Thomas :travelingTo :Paris } :by :Train
>> { :Thomas :travelingTo :Paris } :startTime T1
>> { :Thomas :travelingTo :Paris } :endTime T2
>>
>> The first statement is incomplete, neither true or false, and the second
>> statement has an incomplete statement as subject. What do either of those
>> statements mean? Maybe someone has a better idea, but the only way I
>> currently see around it would be custom expansion rules to do with time and
>> space, which seems ugly to me.
>>
>> With time and space positions it would start as:
>>
>> :Thomas :travelingTo :Paris T1 T2
>>     { :by :Train }
>>
>> Which expands to:
>>
>> :Thomas :travelingTo :Paris T1 T2
>> { :Thomas :travelingTo :Paris T1 T2 } :by :Train
>>
>> Regards
>> Anthony
>>
>> On Fri, Jan 14, 2022 at 12:19 PM Pete Rivett <pete.rivett@agnos.ai>
>> wrote:
>> Fabio, I don't know if it was deliberate, but it seems to me that using
>> different preciates to bound periods such as :start, :end, :after, :before
>> (and more?) seems to defeat the point (and I think what Anthony was looking
>> for) to allow predictable querying and reasoning.
>> I really think it's premature for rdf-star to embody anything like this.
>> I think we should start with a best practice note as suggested (even that
>> will I think be hard enough to reach consensus on), then after sufficient
>> demonstrated success with applying it for real, we could consider
>> standardizing a specific set of predicates in a separate schema.
>> Which also invites the question "what would a schema for
>> rdf-star annotation properties look like, and how could you specify the
>> (required/permitted) use of specific annotation properties with
>> specific regular properties?".
>>
>> BTW nary relationships need not need be as complex as your examples.
>> Simpler alternatives:
>> _:item1 a :temporaryLocation;
>>      :affects :MonaLisa;
>>      :location :Florence;
>>      :hasPeriod [
>>        :start  "1506"^^xsd:Year;
>>        :end  "1517"^^xsd:Year;
>>      ] .
>>
>> _item1 a :USPresidency [
>>    :holder :RichardNixon;
>>    :hasPeriod [
>>     :start "1969-01-20"^^xsd:dateTime ;
>>     :end "1974-08-09"^^xsd:dateTime.
>> ]
>>
>> Cheers,
>> Pete
>>
>> On Thu, 13 Jan 2022 at 09:48, Fabio Vitali <fabio.vitali@unibo.it> wrote:
>> Hi!
>>
>> > On 13 Jan 2022, at 17:04, Pierre-Antoine Champin <
>> pierre-antoine.champin@ercim.eu> wrote:
>> >
>> > Hi Anthony,
>> >
>> > you wrote
>> >
>> > > that the temporal validity of any statement is implicitly
>> lower-bounded by the existence of the things that it talks about,       so
>> technically the birth-date example is only valid after the birth date of
>> the person
>> >
>> > Ok, let's take another example:
>> >
>> > :theWebConf2022 a s:Event ;
>> >     s:startDate "2022-04-25"^^xsd:date ;
>> >     s:endDate "2022-04-29"^^xsd:date .
>> >
>> > would you consider that those triple will only be valid on 2022-04-25?
>> Or would you argue that this event already exists, even though it has not
>> occurred yet?
>> >
>> > Without starting to count angels on pinpoints (wondering if a
>> yet-to-be-born person exists or not), let's be pragmatic: does it make your
>> knowledge base inconsistent in any way to consider that such triples about
>> future events are already valid? I don't think so.
>>
>> You are adding two more pairs of terms, "valid / non valid" and "exist /
>> not exist", to an already complex issue. The pairs already in play are:
>>
>> 1) true / false (or not-true?)
>> 2) asserted / not-asserted.
>>
>> True / not true attain to the relationship between statements and reality
>> (or at least some notion of reality endorsed by logicians and a few
>> mathematicians). Asserted / not asserted attain to whether we know that the
>> current dataset contains the statement or not.
>>
>> [ Valid / not valid attain to correctness in expressing statements (e.g.,
>> according to an ontology), and exist /not exist attain to physical or
>> philosophical understanding of reality which makes my mind quiver (Does
>> Mickey Mouse exist?). ]
>>
>> I understand that here is a traditional, albeit vague, connection in this
>> community between asserted and true, which I respect and uphold. But
>> whatever is the contrary of true, I do not think there should be a similar
>> connection between non-asserted and false (or not true).
>>
>> Non-asserted triples can be absolutely true (<< :theWebConf
>> dc:subject :webTechnologies >>), absolutely false (<< :theWebConf
>> :frontFor :mossadRecruitment >> ), and conditionally true (<< :theWebConf
>> :rating :FiveStars >> ), depending on a lot of factors (time, location,
>> provenance, confidence, etc.), and since rdf-star allows us to represent
>> triples without asserting them, we can use it to express facts about
>> non-asserted triples without worrying about their actual truth:
>>
>> << :theWebConf dc:subject :webTechnologies >>   :accordingTo :wikipedia.
>> << :theWebConf :frontFor  :mossadRecruitment >> :accordingTo :someMadman.
>> << :theWebConf :rating    :FiveStars >>         :accordingTo
>> :FabioVitali.
>>
>> These triples are all asserted (and true (and valid!)) regardless of the
>> truth value of their quoted triples. This is exactly what makes rdf-star
>> very interesting to me.
>>
>> Now, using :theWebConf as in your example is somewhat misleading: you
>> are using an Event, which is an abstract concept of something whose
>> main characteristic is being temporally and geographically constrained, and
>> then you ask if there are other temporal constraints associated to it. No,
>> no, probably not. But you put yourself in an easy situation.
>>
>> Let's try with entities which are not events: say, a physical object, a
>> role, a relationship:
>>
>> << :monaLisa :location :Florence >>
>> << :USA :president :RichardNixon >>
>> << :MickeyMouse inLoveWith :MinnieMouse >>
>>
>> All these triples are NOT absolutely true, and at the same time they are
>> NOT absolutely false, either.
>>
>> Using rdf-star, we can create absolutely-true statements out of these
>> non-absolutely-true triples:
>>
>> << :monaLisa :location :Florence >> :after "1506"^^xsd:Year;
>> :before "1517"^^xsd:Year .
>> << :USA :president :RichardNixon >> :start "1969"^^xsd:Year;
>> :end "1974"^^xsd:Year .
>> << :MickeyMouse inLoveWith :MinnieMouse >> :accordingTo :WaltDisney .
>>
>> These are trivial rdf-star representations of (simple) anthony-statements
>> (syntax aside). I fail to see a downside to this.
>>
>> The opposite, to adopt "dead-simple statements" seems much worse to
>> me: adopting n-ary relationships and events and states and opinions seems
>> SO MUCH MORE COMPLICATED:
>>
>> _:item1 a :temporaryLocation;
>>      :affects :monaLisa;
>>      :location :Florence;
>>      :start [
>>          a :uncertainDate ;
>>          :after "1506"^^xsd:Year;
>>      ] ;
>>      :end [
>>          a :uncertainDate ;
>>          :before "1517"^^xsd:Year;
>>      ] .
>>
>> _:item2 a :temporaryState;
>>      :role :presidency;
>>      :organization :USA;
>>      :holder :RichardNixon;
>>      :startingEvent [
>>         a :election;
>>         :date "1969-01-20"^^xsd:dateTime.
>>      ];
>>      :endingEvent [
>>         a :resignation;
>>         :date "1974-08-09"^^xsd:dateTime.
>>       ].
>>
>> _:item3 a :fictitiousCouple;
>>      :member :MickeyMouse;
>>      :member :MinnieMouse;
>>      :type :Love;
>>      :inventedBy :WaltDisney.
>>
>> You may feel safer with n-ary relationships, i.e. with the
>> objectification of relationships into abstract entities, but another way to
>> express this concept is as "reification of triples into blank nodes" which
>> seems to me exactly what rdf-star is about.
>>
>> We have rdf-star. Let's use it.
>>
>> Ciao
>>
>> Fabio
>>
>> >
>> > So I am still not convinced that triples are the right level of
>> granularity for systematically attaching contextual metadata. Following
>> Pat, I prefer to keep rdf-statements dead-simple (1), and model more
>> complex things (like anthony-statements) with a bunch of triples.
>> >
>> >   pa
>> >
>> > (1) even if, arguably, RDF-star makes them a little more complex that
>> they originally were.
>> >
>> > On 13/01/2022 03:51, Anthony Moretti wrote:
>> >> Earlier I wrote:
>> >> the temporal validity of any statement is implicitly lower-bounded by
>> the existence of the things that it talks about
>> >>
>> >> I wouldn't mind some feedback on this, but I think the temporal
>> validity of every statement has an implicit upper bound too:
>> >>
>> >> Implicit lower bound: Existence of the things being described.
>> >> Implicit upper bound: Stated time of assertion, otherwise the present.
>> >>
>> >> If that's correct, I can use it to demonstrate optional time and space
>> positions:
>> >>
>> >> It's 2010, and Pierre-Antoine sends me a graph. He puts a timestamp on
>> his graph by upper-bounding the temporal validity:
>> >>
>> >> {
>> >>     :BarackObama :presidentOf :UnitedStates 2009 _,
>> >>     :JoeBiden :vicePresidentOf :UnitedStates 2009 _,
>> >>     :HillaryClinton :secretaryOfStateOf :UnitedStates 2009 _,
>> >> }
>> >>     _ 2010
>> >>
>> >> It's now 2022, and I'm working on my own graph:
>> >>
>> >> {
>> >>     :JoeBiden :presidentOf :UnitedStates 2021 _,
>> >>     :KamalaHarris :vicePresidentOf :UnitedStates 2021 _,
>> >>     :AntonyBlinken :secretaryOfStateOf :UnitedStates 2021 _,
>> >> }
>> >>
>> >> I trust Pierre-Antoine and remember that he sent me a graph a long
>> time ago. I do the laziest thing possible and import it unmodified as a
>> compound statement. The information is incomplete but the OWA means
>> everything is ok, and the graph is still valid:
>> >>
>> >> {
>> >>     {
>> >>         :BarackObama :presidentOf :UnitedStates 2009 _,
>> >>         :JoeBiden :vicePresidentOf :UnitedStates 2009 _,
>> >>         :HillaryClinton :secretaryOfStateOf :UnitedStates 2009 _,
>> >>     }
>> >>         _ 2010,
>> >>     :JoeBiden :presidentOf :UnitedStates 2021 _,
>> >>     :KamalaHarris :vicePresidentOf :UnitedStates 2021 _,
>> >>     :AntonyBlinken :secretaryOfStateOf :UnitedStates 2021 _,
>> >> }
>> >>
>> >> I do automated flattening of the graph. The information is incomplete,
>> but the graph is still valid:
>> >>
>> >> {
>> >>     :BarackObama :presidentOf :UnitedStates 2009 2010,
>> >>     :JoeBiden :vicePresidentOf :UnitedStates 2009 2010,
>> >>     :HillaryClinton :secretaryOfStateOf :UnitedStates 2009 2010,
>> >>     :JoeBiden :presidentOf :UnitedStates 2021 _,
>> >>     :KamalaHarris :vicePresidentOf :UnitedStates 2021 _,
>> >>     :AntonyBlinken :secretaryOfStateOf :UnitedStates 2021 _,
>> >> }
>> >>
>> >> I finally get the motivation and I update Pierre Antoine's statements.
>> The information is now up to date and the graph is still valid:
>> >>
>> >> {
>> >>     :BarackObama :presidentOf :UnitedStates 2009 2017,
>> >>     :JoeBiden :vicePresidentOf :UnitedStates 2009 2017,
>> >>     :HillaryClinton :secretaryOfStateOf :UnitedStates 2009 2013,
>> >>     :JoeBiden :presidentOf :UnitedStates 2021 _,
>> >>     :KamalaHarris :vicePresidentOf :UnitedStates 2021 _,
>> >>     :AntonyBlinken :secretaryOfStateOf :UnitedStates 2021 _,
>> >> }
>> >>
>> >> I decide to send it back to Pierre-Antoine, and I put a timestamp on
>> my graph:
>> >>
>> >> {
>> >>     :BarackObama :presidentOf :UnitedStates 2009 2017,
>> >>     :JoeBiden :vicePresidentOf :UnitedStates 2009 2017,
>> >>     :HillaryClinton :secretaryOfStateOf :UnitedStates 2009 2013,
>> >>     :JoeBiden :presidentOf :UnitedStates 2021 _,
>> >>     :KamalaHarris :vicePresidentOf :UnitedStates 2021 _,
>> >>     :AntonyBlinken :secretaryOfStateOf :UnitedStates 2021 _,
>> >> }
>> >>     _ 2022
>> >>
>> >> And so it could continue. Spatial validity would be handled similarly.
>> >>
>> >> It's very easy to reason about temporal/spatial validity when the
>> approach to statements is unified and optional time and space positions can
>> be used everywhere.
>> >>
>> >> Regards
>> >> Anthony
>> >>
>> >> On Wed, Jan 12, 2022 at 12:48 PM Anthony Moretti <
>> anthony.moretti@gmail.com> wrote:
>> >> Correction, I was a bit sloppy:
>> >>
>> >> In both cases I would leave the time and space positions blank anyway,
>> so RDF-as-usual.
>> >>
>> >> In the second example the space position would be blank, but not the
>> time positions. I was just trying to agree that yes the second example
>> isn't place-dependent.
>> >>
>> >> Regards
>> >> Anthony
>> >>
>> >> On Wed, Jan 12, 2022 at 12:44 PM Anthony Moretti <
>> anthony.moretti@gmail.com> wrote:
>> >> Hi Pierre-Antoine
>> >> What is not entirely clear to me is how you see the ideas below
>> interact with RDF-star —or RDF, for that matter...
>> >>
>> >> 1) Do you want to modify the core of RDF / RDF-star, replacing their
>> notion of statement by the one you propose here (time+place annotated,
>> complex and/or compound)?
>> >>
>> >> 2) Or do you want to explore how your proposed notion of statement
>> could be expressed *on top* of RDF / RDF-star, with no or minimal
>> modification to them?
>> >>
>> >> If the answer is 2 (my favorite option, by the way), then the idea is
>> to model anthony-statements using a set of rdf-statements (possibly
>> extended with RDF-star).
>> >>
>> >>
>> >> Ideally:
>> >> RDF: Time and space positions.
>> >> RDF-Star: Simple, compound, and complex statements.
>> >>
>> >> It would be ideal to put the time and space positions at the RDF level
>> because, as Pat and Fabio seem to agree, some triples are time/space
>> dependent and make no sense without that information. They're not edge
>> cases either, it might seem like that because so far there hasn't been a
>> way to express them, but there are infinitely many just as there are
>> infinitely many that aren't time/space constrained. Also, the order of
>> assertion is important for time/space dependent triples, if anything is to
>> be said about them, additional data or metadata, then the time/space
>> constraints need to be asserted first, and time and space positions ensure
>> that order of assertion.
>> >>
>> >> I think it would help the discussion a lot to a) acknowledge that the
>> word "statement" in this discussion is ambiguous, and b) to be as explicit
>> as possible about which kind we are talking about.
>> >>
>> >> I'm using the word "statement" as a direct replacement for "sentence",
>> so maybe "sentence" is a better term:
>> >>
>> >> sentence:
>> >> a set of words that is complete in itself, typically containing a
>> subject and predicate, conveying a statement, question, exclamation, or
>> command, and consisting of a main clause and sometimes one or more
>> subordinate clauses.
>> >>
>> >> I am uncomfortable with "hard-coding" these 4 dimensions, and only
>> them, in every possible statement. I think that the relevant dimensions
>> depend on the relation itself (e.g., the birth-date of a person is neither
>> time nor place dependent; the president of a country is not place
>> dependent...). And I don't think that any list of contextual dimension can
>> be exhaustive.
>> >>
>> >> Especially regarding certainty, there are many ways to model
>> uncertainty (not all of them modelling it with a single value between 0 and
>> 1, by the way).
>> >>
>> >>
>> >> On the first example you gave, my thoughts are that the temporal
>> validity of any statement is implicitly lower-bounded by the existence of
>> the things that it talks about, so technically the birth-date example is
>> only valid after the birth date of the person, the birth date happens to be
>> the object of the statement in this case but the idea would apply to any
>> statement. On the second example, yes I agree its spatial validity is
>> unbound. In both cases I would leave the time and space positions blank
>> anyway, so RDF-as-usual.
>> >>
>> >> I'm happy to drop "certainty" for the reasons you stated. I've
>> included it so far because it's another example of where order of assertion
>> becomes important, for it to make sense it needs to be asserted after time
>> and space but before metadata. But yes, let's drop it for now.
>> >>
>> >> And yes for sure, no list of contextual dimensions can be exhaustive,
>> but if time and space positions are allowed it ensures those assertions are
>> made first and the whole framework becomes scalable and easier to reason
>> about.
>> >>
>> >> Do you have any clear definition, or at least guidelines, to decide
>> whether a piece of information is additional data or metadata?
>> >>
>> >> My quick take would be: additional data continues the description,
>> whereas metadata is description of the description.
>> >>
>> >> No widespread need, but logically it could continue, descriptions of
>> descriptions of descriptions and so on:
>> >>
>> >> Simple statement
>> >>     { Additional data }
>> >>     {| First-order metadata |}
>> >>     {| Second-order metadata |}
>> >>     ...
>> >>
>> >> Fabio has a good idea with the note containing examples of good
>> modeling.
>> >>
>> >> Regards
>> >> Anthony
>> >>
>> >> On Wed, Jan 12, 2022 at 8:02 AM Fabio Vitali <fabio.vitali@unibo.it>
>> wrote:
>> >> Dear Pierre-Antoine,
>> >>
>> >> > 1) Do you want to modify the core of RDF / RDF-star, replacing their
>> notion of statement by the one you propose here (time+place annotated,
>> complex and/or compound)?
>> >>
>> >>
>> >> I think with you that RDFstar already provides a lot of what has been
>> discussed so far.
>> >>
>> >> Yet Anthony explicitly mentions (and I agree with him) that RDFstar
>> has the right approach for single triples, but is lacking in supporting the
>> needs for complex and compound statements. Working towards some suggestions
>> to integrate these needs would enrich and complete the RDFstar proposal.
>> >>
>> >> My preference would go towards exploiting named graphs, explicitly
>> introducing unasserted named graphs that can then be used in RDFstar in the
>> same way of unasserted triples.
>> >>
>> >> > 2) Or do you want to explore how your proposed notion of statement
>> could be expressed *on top* of RDF / RDF-star, with no or minimal
>> modification to them?
>> >>
>> >> I do not know Anthony's point of view on this, but I believe that it
>> would be useful to think of a resource providing some thoughtful and
>> general guidelines on how RDFstar's quoted and annotated triples (as well
>> as, hopefully, the RDFstar's quoted and annotated named graphs that I
>> envision) could help in expressing conditional, time-dependent,
>> location-dependent, uncertain, opinionated and competing statements.
>> >>
>> >> What I am thinking is something like, say, a W3C note, on the lines of
>> https://www.w3.org/TR/swbp-n-aryRelations/ : a document introducing no
>> new features, but explaining and making examples on how to use the existing
>> features in a possibly unexpected and innovative way.
>> >>
>> >> What do you think?
>> >>
>> >> Fabio
>> >>
>> >> --
>> >>
>> >> > On 11 Jan 2022, at 15:43, Pierre-Antoine Champin <
>> pierre-antoine.champin@ercim.eu> wrote:
>> >> >
>> >> > Hi Anthony,
>> >> >
>> >> > thanks for the summary. It's hard to catch up for those of us who
>> went offline during the break :-)
>> >> >
>> >> > On 08/01/2022 10:40, Anthony Moretti wrote:
>> >> >> Hi
>> >> >>
>> >> >> I thought I'd put the ideas I shared during the longer discussion
>> in one place to make it easier for people to read and give feedback. I love
>> what's been achieved so far, I just want whatever is released to be the
>> best possible thing that could be released.
>> >> > What is not entirely clear to me is how you see the ideas below
>> interact with RDF-star —or RDF, for that matter...
>> >> >
>> >> > 1) Do you want to modify the core of RDF / RDF-star, replacing their
>> notion of statement by the one you propose here (time+place annotated,
>> complex and/or compound)?
>> >> >
>> >> > 2) Or do you want to explore how your proposed notion of statement
>> could be expressed *on top* of RDF / RDF-star, with no or minimal
>> modification to them?
>> >> >
>> >> > If the answer is 2 (my favorite option, by the way), then the idea
>> is to model anthony-statements using a set of rdf-statements (possibly
>> extended with RDF-star). I think it would help the discussion a lot to a)
>> acknowledge that the word "statement" in this discussion is ambiguous, and
>> b) to be as explicit as possible about which kind we are talking about.
>> >> >
>> >> > I also have a few comments on the two first ideas:
>> >> >
>> >> >> (...)
>> >> >>
>> >> >> Summary:
>> >> >> 1. Optional time, space, and certainty positions.
>> >> > I am uncomfortable with "hard-coding" these 4 dimensions, and only
>> them, in every possible statement. I think that the relevant dimensions
>> depend on the relation itself (e.g., the birth-date of a person is neither
>> time nor place dependent; the president of a country is not place
>> dependent...). And I don't think that any list of contextual dimension can
>> be exhaustive.
>> >> >
>> >> > Especially regarding certainty, there are many ways to model
>> uncertainty (not all of them modelling it with a single value between 0 and
>> 1, by the way). On that particular topic, you might be interested in this
>> paper:
>> https://hal.inria.fr/hal-02167174/file/Publishing_Uncertainty_on_the_Semantic_Web__Bursting_the_LOD_bubbles__Final_Version_.pdf
>> >> >
>> >> >> 2. Separating additional data from metadata.
>> >> > Do you have any clear definition, or at least guidelines, to decide
>> whether a piece of information is additional data or metadata?
>> >> >
>> >> >   best
>> >> >
>> >> >> 3. Simple, compound, and complex statements.
>> >> >> - - -
>> >> >>
>> >> >> 1. Optional time, space, and certainty positions
>> >> >>
>> >> >> We exist in time and space, and this type of modeling could
>> possibly be easier. A statement would have four optional positions, leaving
>> the time and space positions blank would mean "unbounded", and leaving the
>> last position blank would mean 1.0:
>> >> >>
>> >> >> Subject Relation Object T1 T2 SpatialBound Certainty
>> >> >>
>> >> >> Examples:
>> >> >>
>> >> >> :RichardB :marriedTo :LizT 1964 1974
>> >> >> :RichardB :marriedTo :LizT 1975 1976
>> >> >>
>> >> >> :BigMac :price-USD 7.30 T1 T2 :Switzerland
>> >> >> :BigMac :price-USD 1.62 T1 T2 :India
>> >> >>
>> >> >> If anybody has worked with temporal databases they might see an
>> analogy with "valid times". By extension, the spatial bound could be
>> thought of as a "valid place".
>> >> >>
>> >> >> 2. Separating additional data from metadata
>> >> >>
>> >> >> This would remove a lot of ambiguity and creates a clear order of
>> assertion. It also seems to match the Wikidata data model.
>> >> >>
>> >> >> Example:
>> >> >>
>> >> >> :LizT :starredIn :JaneEyre
>> >> >>     {
>> >> >>         :role :HelenBurns,
>> >> >>         :pay-USD 10000,
>> >> >>     }
>> >> >>     {|
>> >> >>         :statedBy :Bob,
>> >> >>         :statedIn :Wikipedia,
>> >> >>     |}
>> >> >>
>> >> >> 3. Simple, compound, and complex statements
>> >> >>
>> >> >> Taking inspiration from linguistics, there could be four different
>> types of statements:
>> >> >>
>> >> >> 1. Simple statement
>> >> >> 2. Compound statement
>> >> >> 3. Complex statement
>> >> >> 4. Compound-complex statement
>> >> >>
>> >> >> Simple statement (binary relationship):
>> >> >> S R O T1 T2 SB C
>> >> >>
>> >> >> Compound statement (graph):
>> >> >> {
>> >> >>     S R O T1 T2 SB C,
>> >> >>     S R O T1 T2 SB C,
>> >> >>     S R O T1 T2 SB C,
>> >> >> }
>> >> >>     T1 T2 SB C
>> >> >>
>> >> >> Complex statement (n-ary relationship):
>> >> >> S R O T1 T2 SB C
>> >> >>     {
>> >> >>         R O T1 T2 SB C,
>> >> >>         R O T1 T2 SB C,
>> >> >>     }
>> >> >>
>> >> >> Compound-complex statement (n-ary relationship):
>> >> >> {
>> >> >>     S R O T1 T2 SB C,
>> >> >>     S R O T1 T2 SB C,
>> >> >>     S R O T1 T2 SB C,
>> >> >> }
>> >> >>     T1 T2 SB C
>> >> >>     {
>> >> >>         R O T1 T2 SB C,
>> >> >>         R O T1 T2 SB C,
>> >> >>     }
>> >> >>
>> >> >> This creates consistency, and makes it easy to reason about
>> the temporal/spatial validity of any graph.
>> >> >>
>> >> >> The existing RDF-Star "<<" and ">>" delimiters could be applied
>> to statements of any type to say that a statement was "neutrally asserted",
>> as I think Pat has described it before. Maybe for completeness, and based
>> on something Pat published, other delimiters could be created that would
>> mean "negatively asserted", something like "<!" and "!>" for example.
>> >> >>
>> >> >> The existing RDF-Star "{|" and "|}" delimiters could be applied to
>> statements of any type to add metadata. The example in Section 2 of this
>> email is an example of a complex statement with metadata.
>> >> >>
>> >> >> And I'm not sure, but it seems that nesting statements could be a
>> general solution to contexts, the deepest nested statements would be in the
>> most specific contexts. I haven't examined it properly though.
>> >> >>
>> >> >> If you've made it here thanks for reading! If you need more
>> examples please ask and I'll do my best. I love everything done so far, I
>> just want to bounce around these additional ideas with the hope that
>> they're constructive. Please reply with any feedback at all, good and bad,
>> it's all welcome!
>> >> >>
>> >> >> Regards
>> >> >> Anthony
>> >> > <OpenPGP_0x9D1EDAEEEF98D438.asc>
>> >>
>> > <OpenPGP_0x9D1EDAEEEF98D438.asc>
>>
>>
>>
>>
>