Re: Three ideas

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>
>
>