- From: Alan Ruttenberg <alanruttenberg@gmail.com>
- Date: Tue, 18 Jan 2011 22:55:39 -0500
- To: Dave Reynolds <dave.e.reynolds@gmail.com>
- Cc: nathan@webr3.org, public-lod@w3.org
On Tue, Jan 18, 2011 at 3:47 AM, Dave Reynolds <dave.e.reynolds@gmail.com> wrote: >> As for RIF and GRDDL, can anybody point me to the reasons why >> normalization are not performed, does this have xmlns heritage? > > Not as far as I know. At least in RIF we were just trying to b > compatible with the RDF specs which (cwm not withstanding) do not > specify normalization other than the IRI-compatible character encoding. > Similarly OWL. OWL says, following the sense of the anticipation of the IRI spec: "Two IRIs are structurally equivalent if and only if their string representations are identical." As far as I can tell, you (Dave) are the only person in this conversation who cites the specification relevant to answering the question posed. That specification makes clear, as you have cited, exactly how RDF interpreters are to compare URI references. The information on how to fully determine equivalence according to the URI spec is distributed across a wide and growing number of different specifications (because it is schema dependent) and could, in principle, change over time. Because of the distributed nature of the information it is not feasible to fully implement these rules. Optionally implementing these rules (each implementor choosing where on the ladder they want to be) would mean that documents written in RDF (and derivative languages) would be interpreted differently by different implementations, which is an unacceptable feature of languages designed for unambiguous communication. The fact that the set of rules is growing and possibly changing would lead to a similar situation - documents that meant one thing at one time could mean different things later, which is also unacceptable, for the same reason. David (Wood) clarifies (surprisingly to me as well) that the issue of normalization could be addressed by the working group. I expect, however, that any proposed change would quickly be determined to be counter to the instructions given in the charter on Compatibility and Deployment Expectation, and if not, would be rejected after justified objections on this basis from reviewers outside the working group. -Alan
Received on Wednesday, 19 January 2011 03:56:28 UTC