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Re: my comments on the "Property Paths" document

From: Andy Seaborne <andy.seaborne@talis.com>
Date: Mon, 11 Jan 2010 10:27:34 +0000
Message-ID: <4B4AFD16.3070305@talis.com>
To: Souripriya Das <SOURIPRIYA.DAS@oracle.com>
CC: public-rdf-dawg@w3.org
On 11/01/2010 2:42 AM, Souripriya Das wrote:
> My comments for the Property Paths document:
>     * Section 2: Outstanding Issues
>           o [typo] "includeds" => "includes"

Done (and this section will disappear)

>           o [my opinion regarding the "^" operator] exclude its binary
>             version and keep only the unary version

Noted in the issues section.

>     * Section 3: Path Language
>           o [typo] "an path element" => "a path element"


>     * overall
>           o [why not allow variables? is it because it introduces
>             complexity?] If we do not allow variables, we lose in
>             functionality because then we cannot *find* the (distinct)
>             properties connecting two nodes (e.g., via an unknown or
>             non-fixed length path). [Note: Specifically, we are just
>             asking for the distinct properties that constitute a path.
>             We are *not* trying to retrieve the path itself.]
>                 + Example: {?x (?p)+ ?y}would allow us to find the
>                   properties (if any) each of which make up a distinct
>                   path from the source node to the target node. (Note:
>                   0-length path may not be very useful in this case.)

Wouldn't that be a path with the same property (?p) at each path step? 
e.g. foaf:knows - so it's not any path from ?x to ?y which is my reading 
of the text explaining it.  Or (?p)+ means something different from the 
"sequence of one or more ?p".

>                 + Example: {?x (?p)+/(?q)* ?y . FILTER (?p != ?q)}will
>                   give us property ?p that make up a single-property
>                   path between the two nodes, or a property pair (?p,
>                   ?q) such that a ?p-based path concatenated with a
>                   ?q-based path connects the two nodes.

Souri - there was a strawpoll of possible starting points for the 
property path work. This included variables in the property position.


Strawpoll results:

and discussion in email around that time.

The strawpoll showed most support for not considering variables in path 
sat this time.  The syntax does not prclude it in the future.

>     * Section 5.2: Complex Paths
>           o [suggestion] Can we replace the resource, <http://example/>,
>             used in the second example, { <http://example/>
>             rdf:type/rdfs:subClassOf* ?type }, with foaf:alice or
>             something like that.

foaf: is the namespace of FOAF vocabulary.  It would be strange for 
individuals (e.g. alice) to be in that namespace.

I have changed it to <http://example/thing> in case the concern is the 
use of http://example/.


> Thanks,
> - Souri.
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Received on Monday, 11 January 2010 10:28:01 UTC

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