Two comments on the RDF documents from Bob MacGregor on 2003-01-28 (www-rdf-comments@w3.org from January to March 2003) (original) (raw)

In examining the RDFCore documents, I have found two sections where I believe the language needs to be rewritten.

In the excerpt below from the RDF Primer, I believe that the use of double brackets in the example is misleading, and should be replaced by something else. It illustrates a statement syntactically nested within another statement. There is nothing in the current RDF equivalent to such a construct. It preceeds a discussion of reification, which might lead a reader to believe that RDF's notion of a reified statement (a "stating") is somehow related to this kind of nesting.

 RDF Primer
 4.3 RDF Reification
 Now, suppose we wanted to say in RDF that this statement was made by John
 Smith. Since in RDF we can only make statements about resources, what 

we would like to be able to do is write something like:

  [[exproducts:item10245  exterms:weight  "2.4" .]] 

dc:creator exstaff:85740 .

Here are two quotes from Pat Hayes' emails:

" ... rather like saying that the ability to sing eliminates the need to stand on one foot. Nesting hasn't got anything to do with reification."

"Many people have suggested using reification to simulate expression nesting in recursive syntax, but this kind of usage for reification was a mistake from the start."

Pat is claiming that reification and nested statement syntax have nothing to do with each other, while the excerpt from 4.3 uses nesting as a lead-in to a discussion on reification. While my personal belief is that there IS a connection, I will affirm that nested statements do not correlate with the notion of a "stating" that RDF has adopted. Hence my recommendation that the example of nested syntax be replaced by something else.

I have a problem with the following discussion in the Concepts and Abstract Syntax document:

 Concepts and Abstract Syntax
 4.1 Asserted and Non-Asserted Forms

 Not every RDF/XML expression is asserted. Some may convey meaning that 

is partly determined by the circumstances in which they are used. For example, in English, a statement "I don't believe that George is a clown" contains the words "George is a clown", which, considered in isolation, has the form of an assertion that George exhibits certain comic qualities. However, considering the whole sentence, no such assertion is considered to be made.

First, I don't believe that the statement "I don't believe that George is a clown" is expressible in RDF. I am happy to be proved wrong, in which case would someone please show me an illustration of it?

Second, the discussion in 4.1 does not provide any examples in RDF of expressions that are not asserted. Hence, whether or not the "I don't believe ..." statement can be expressed, the discussion ought to contain SOME example in RDF of a non-asserted RDF expression.

Cheers, Bob

Received on Tuesday, 28 January 2003 15:06:41 UTC