> I know about the serialization formats and none of them will fit my needs because the problem lies in the data model, not a concrete syntax. I don't really understand the point you try to make about literals.
So create your own serialization format suited to your own needs.
> I don't really understand the point you try to make about literals. Mine is that because literals cannot be the origin of an edge, they form sinks. And that's very annoying for building a graph (of strings) because you then need to create proxy nodes for data all the way up.
If by origin you mean what RDF calls subject then yes, as I said, the RDF data model does not support subject literals. That is by design. What you could do is create a resource that encapsulates strings in the way you want a use that for both the subject and object. Don't think them as proxy nodes, think of it like you now have the ability decorate your string literals in an extensible way.
> For annotations, you can read[1]. What I meant however a really simple graph construct: information on edges. In the Neo4j lingo that is called a property[2]. There absence in RDF make it difficult to represent situations such "Paris"---distance:54---"Rennes".
PREFIX distance:
[wdt:Q90 distance:354 wdt:Q647]
Because Paris and Rennes are already in Wikidata, why not use them? Create your own namespace, call the distance property "distance" when you're prefixing it, reserve numerals in this property to signify geographical magnitude in km. 354 between Paris and Rennes, not 54?
> I'm visibly not the only one it's itching[5].
Two wrongs don't make a right. Considering that link was calling for this in 2010 suggest to me that you oughtn't hold your breath. Also them self-describing as an expert is crass.
> Yes you can use URN, be some projects doesn't support them.
Well, that is not the fault of RDF now is it?
> Moreover, renting a domain (you can't buy a domain name) may be cheap but why putting this burden on yourself if you can avoid it?
If you can't afford €10 per year or the institution where your project is located can't afford it then you have bigger problems than imaginary RDF restrictions.
> Anyway I'll be curious to see something you built with RDF, if any. I failed to find your work besides two papers that aren't related to the subject.
I've used Wikidata and DBpedia to build a corpus of philosophers and their philosophical texts without too much of a problem once I wrapped my head around how RDF and SPARQL work.
Paris on Wikidata: https://www.wikidata.org/wiki/Q90
Rennes on Wikidata: https://www.wikidata.org/wiki/Q647