RDF/A Syntax: comments on 27 October 2005 version

I've read the 27 October 2005 draft of RDF/A Syntax and do have the 
following technical comments. Also, are there any patent statements in 
relation  to this technology, and what reference implementations are 
available?

        http://www.w3.org/2001/sw/BestPractices/HTML/2005-rdfa-syntax

Thanks & Season's greetings,
Christian (disclaimer: RDF/A newcomer :)


#1 
section 2.3: According to first two paragraphs in section 4.3.3 the link 
element would have to be reified, thus leading to 6 (not 2) triplets 
overall.

#2 
section 2.4: How should abiguities between CURIEs and URIs been resolved 
within the scope of this specification? The XML sniplet in section 2.4 
suggests that CURIEs appear in square brackets, but e.g. the 5th sniplet 
in section 3.1 has no such brackets. There are also cases (e.g. last 
sniplet in section 5.2 which contain unbracketed URIs with colons which 
must not be resolved as CURIEs. With this mixed conventions it would 
appear that a resolution mechanism for RDF/A has to have knowledge about 
"common" schema names (such as mailto), which seems undesirable. A better 
alternative may be to require that all CURIEs be bracketed.

#3 
section 3.1: According to section 5.1.1.1 the 3rd object in the 12th XML 
sniplet would have to be written as "Portrait of Mark"^^rdf:XMLLiteral 
(not "Portrait of Mark") when obtained from either of the last two RDF/A 
examples in this section (but not when obtained from the 11th XML 
sniplet).  If "string" serves as a shorthand notation for 
"string"^^rdf:XMLLiteral, the document should say so, because it uses both 
versions (e.g. the last XML sniplet in section 5.1.1 cites "Mark 
Birbeck"^^rdf:XMLLiteral).

#4
section 4.1, 2nd paragraph: The upper limit of 3 triplets per RDF/A 
element only applies if you do not consider subject reification (which 
would lead to 4 additional triplets per reified statement).

#5 
section 4.2.1: The meta element's closing tag is missing from the XML 
sniplet (add "/>").

#6 
section 4.3: The document defines [RDF/A element] in section 2.2, but 
sometimes refers to [RDF/A statement] instead.

#7 
section 4.3.3: What namespaces do the meta and link tags have to belong 
to? Any, none, the XHTML namespace, ... ?

#8 
section 4.3.3, 3rd paragraph: According to section 4.1, an [RDF/A element] 
can generate up to 3 triplets. Which triplet stemming from the context 
statement ought to be reified as the subject under the circumstanced 
detailed in the 3rd paragraph? Maybe the language in the 3rd paragraph 
should also say: "... the RDF triplet represented by the [context 
statement] ..." (not "the [RDF/A statement]"). Or does [RDF/A statement] 
implicitly refer to a set of triplets?

#9 
section 4.3.3: Add definition or reference to [unique anonymous ID].

#10 
section 4.4.2: What's the prescribed behavior of an RDF/A reader it the 
href attribute were missing from the XML sniplet in this section?

#11
section 5.1.1.1: Why would the leading and trailing whitespaces (e.g. 
before "E = mc...") disappear during exclusive canonicalization? Add a 
reference and give more detail on which exact node set should undergo 
canonicalization (perhaps specify as XPath expression). What charset 
should be used (e.g. UTF-8)?

#12
section 5.1.1.1: reference to RDF/A element's value misleading, because 
it's really a DOM subtree (including two sup elements, etc.) or node set.

#13 
section 5.1.1.1: The 4th XML sniplet should list 2 triplets, the other 
stating that Einstein created "<>".

#14
section 5.2, 2nd paragraph: typo in "exapmle"

#15 
section 5.2: Define or provide reference to explain syntax that uses 
underscore namespace prefixes, as e.g. in "_:a" (anonymous).

#16
section 5.3: Add document that defines reification to bibliography (e.g. 
RDF Semantics).