Re: Three ideas

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