Re: on lists

Hi Holger

on your historical issue:


> On Oct 15, 2016, at 8:57 PM, Holger Knublauch <holger@topquadrant.com> wrote:
> 
> It is a bit surprising that there doesn't seem to be a standard definition of what a well-formed rdf:List is.


Back in 2004 time-frame, the RDF group felt that it was out of scope because the ‘obvious’ constraints were simply not the sort of complex syntactical constraint at a graph level that the group felt were in scope for that group.
If when you merge graphs, apply inferences, etc etc you get an ill-formed list, what do you do?
i.e. the RDF Core WG was aware of the problem of ill-formed lists and made an explicit decision that it was not within the focus of the work

On the other hand, the OWL WG, were schizophrenic, with the DL/Lite versions simply regarding the triples as a projection of the real OWL syntax: in this projection all lists are well formed, but you cannot use rdf lists as a general data structure.
In OWL Full, OTOH, constraints are expressed semantically not syntactically, and so the well-formedness constraint for RDF lists was once again out of scope.

It seems to me that this constraint is one of many potential high level syntactic constraints on RDF triples expressing data structures, and I am pleased to see that it is noted as in-scope for the shapes group:

https://www.w3.org/TR/2015/WD-shacl-ucr-20150414/#uc26-rdf-lists-and-ordered-data <https://www.w3.org/TR/2015/WD-shacl-ucr-20150414/#uc26-rdf-lists-and-ordered-data>

This, to me at least, seems to be the appropriate level at which to fix this long-standanding problem.


Jeremy