Annotation Concept vs Document (was Level 1 comments)

Dear all,

To pick up on one of Antoine's comments in particular:

On Sun, Jan 6, 2013 at 8:47 AM, Antoine Isaac <aisaac@few.vu.nl> wrote:

>
> 2. "An Annotation is the expression of a relationship between two or more
> resources in the form of a serialized graph."
> I find this confusing. Serialization is a representation in one syntax.
> This hints that an annotation serialized in RDF/XML is not the same as an
> annotation serialized in Turtle... I would remove "in the form of a
> serialized graph".
>

That is actually the exact intent.  An Annotation is a document, which
necessarily has a serialization.  Therefore the RDF/XML serialization of a
graph, from URI-A, is a different "Annotation" from the same graph
serialized in JSON-LD from URI-B.

This is to avoid having to have multiple nodes, one identifying the
Annotation and the other identifying the serialization.  This was met with
large rounds of disdain from the Linked Data community when it was done in
the Open Archives ORE spec (Conceptual Aggregation vs Resource Map
Document) and necessitates the use of the 303 redirect paradigm.

The two options considered:

(1) Have multiple nodes.  One for the serialization, one for the Annotation
concept.
Costs:
* Have to mint and maintain two identifiers.  People don't like doing this.
Look at the "textual body" discussion!
* Have to have a 303 redirection service
* Have to include both in the graph in order to have the
serializedBy/serializedAt information
* Have to have specific instructions as to what to refer to, Concept or
Serialization, in further Annotations


(2) Have a single identity that represents the serialization
Costs:
* Have to either explain the issue in detail to people who probably don't
care, or gloss over it and hope Antoine doesn't notice :)
* Have to have serializedBy/At and annotatedBy/At to properly maintain the
provenance information

We figured that option (2) was the lesser of the two evils.

The hypothetical option (3) is to have a single identity that represents
the concept, but that would be much harder to justify as to why you got a
representation from a concept.

Our proposed solution is to keep the text in the introduction as is, but
explain the situation further in the Provenance section for people who care
about it.

Rob & Paolo