- From: Michael Schneider <schneid@fzi.de>
- Date: Thu, 27 Sep 2012 01:23:15 +0200
- To: Boris Motik <boris.motik@cs.ox.ac.uk>
- CC: "public-owl-wg@w3.org" <public-owl-wg@w3.org>
Hi Boris!
Am 27.09.2012 00:51, schrieb Boris Motik:
>> 01) RDF Mapping: Table 11 on parsing object property expressions has now an extended condition: "OPE(_:x) = \epsilon". While I don't see an immediate problem with this condition, I don't understand why it has been introduced. In comparison, for class expressions, AFAICT, there are never any conditions on the root blank nodes. I believe it is stated elsewhere, that blank nodes for expressions must not be reused, so this condition seems redundant to me. But there may well be a reason for it.
>>
>
> If OPE(_:x) is not equal to \epsilon, then matching this pattern would redefine OPE(_:x) and we certainly don't want that.
But then, why isn't there a similar condition for the mappings of
/class/ expressions? For example, the mapping rule for class complement
expressions in Table 13 states
If G contains this pattern...
_:x rdf:type owl:Class .
_:x owl:complementOf y .
(*) { CE(y) ≠ ε }
...then CE(_:x) is set to this class expression.
ObjectComplementOf( CE(y) )
Why isn't the condition at (*) not replaced by
(**) { CE(_:x) = ε and CE(y) ≠ ε }
? Looks to me like being basically the same problem, or do I miss something?
Cheers,
Michael
Received on Wednesday, 26 September 2012 23:23:41 UTC