Comments on Last-Call Working Draft of RDF 1.1 Concepts and Abstract Syntax

Dear Working Group!

This is my review of the Last-Call Working Draft of the "RDF 1.1 
Concepts and Abstract Syntax" specification.

Unfortunately, I only learnt about the existence of the LCWDs from their 
announcement on the SWIG mailing list as of 3 October, with an - already 
extended - deadline set to 17 October, which was a very short time and 
did not give me enough time to complete the review in time. I hope that 
you will still accept my review. I will send another review for the RDF 
Semantics specification, which I will hopefully finish till tomorrow. To 
ease the process for you, I have, after a mail exchange with Sandro 
Hawke, created my review based on the most-current editor drafts of the 
two documents:

* <https://dvcs.w3.org/hg/rdf/raw-file/default/rdf-concepts/index.html>
* <https://dvcs.w3.org/hg/rdf/raw-file/default/rdf-mt/index.html>

I'd like to add that I have a high personal and professional stake in 
these two documents.

In general, I consider the "Concepts" document pleasing and don't have 
any real show-stopping issues to report. Still, there are a few issues 
that I consider "major", and a couple that I consider "minor".

Major issues:
-------------

* § 3.3: "a datatype IRI, being an IRI that determines how the lexical 
form maps to a literal value." I do not think that it is correct to 
state that an IRIs would determine how the lexical-to-value mapping 
works. IRIs generally do only denote some resource, in this case a 
datatype. It's the datatype specification which determines the mapping, 
not the IRI that denotes the datatype.

* § 3.1: I believe that the "NOTE" about IRIs, literals and blank nodes 
being distinct should be formally specified in some way, and not just 
"noted".

* § 5.1: Several of the XML datatypes listed seem to be incompatible 
with the definition of a "lexical-to-value mapping" in the beginning of 
§5. According to the definition, "each member of the lexical space is 
paired with exactly one value, and is a lexical representation of that 
value. However, for example the lexical forms of the datatype "xsd:time" 
do not uniquely denote a single time value, but denote an infinite 
number of recurrent time values, one per day (for a fixed time zone). 
Further, for the datatype "xsd:date", it is not clear whether a lexical 
form denotes a single point on the timeline (e.g. the starting point of 
a day), or rather a whole interval of values (the whole day). Variants 
of these problems exist for several of the other listed time-related 
datatypes.

Minor issues:
-------------

* § 1.2, par 1, states that the term "resource" "is synonymous with 
entity". I did not find the term "entity" being mentioned elsewhere in 
the document, nor would I say from my experience that it is widely used 
in the RDF world as a synonym for "resource". So I suggest to remove the 
cited phrase.

* § 1.3, 2nd item: double word: "what what"

* § 3.2, the NOTE: "... that permits a much wider range...": the word 
"much" is redundant and should in my opinion not appear in a specification.

* §4.1: In the introductory sentence, the two datasets D1 and D2 each 
have only a single named graph NG1 and NG2, respectively. This would be 
unnessesarily restrictive. Therefore, and from condition 6 of the 
definition, I guess that NG1 and NG2 are really meant to be /sets/ of 
named graphs for the two datatsets?

* §4.1: Typos in condition 4 of the definition:
   - comma missing in the set defining G
   - the set defining G runs to "1n", which should be "tn" or "Tn"
   - the set defining M(G) runs to "M(T(n))": be careful to use the same
     term ("tn" or "Tn" that is used in the set defining G.

* §5.4: "Semantic conditions of RDF MAY recognize other datatype 
IRIs...". The term "semantic condition" is specific to the RDF Semantics
   and as far as I can see does not appear elsewhere in the Concepts 
document. I think that the sentence should appear only in the RDF 
Semantics and should be removed in the Concepts document.

Best regards,
Michael Schneider

Received on Saturday, 19 October 2013 21:46:38 UTC