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Re: Changes to make S&AS consistent with RDF Semantics document

From: <herman.ter.horst@philips.com>
Date: Fri, 12 Dec 2003 20:57:22 +0100
To: Jim Hendler <hendler@cs.umd.edu>
Cc: connolly@w3.org, pfps@research.bell-labs.com, pat hayes <phayes@ihmc.us>, sandro@w3.org, www-webont-wg@w3.org
Message-ID: <OF5C78982D.4653D560-ONC1256DFA.005D62E6-C1256DFA.006DAB3B@diamond.philips.com>

>All-
> Pat Hayes has sent a response to Herman at
>http://lists.w3.org/Archives/Public/www-rdf-comments/2003OctDec/0234.html
> in the interest of trying to keep from having two competing 
conversations I direct WG members to that

As the following text shows,
Pat did not accept the suggestion that RDF would become a 
more flexible basis for the Semantic Web if it would
only be an option for RDFS reasoners (and thereby also OWL
reasoners) to support XMLLiteral, and not a strict requirement as 
it is currently.

PatH>... and the documents have drawn explicit attention to it.  The 
language 
>was designed this way deliberately, as a result of WG decisions made 
>partly in response to other comments; so to change this at this stage 
>would be a major re-design.  Webont had adequate time to comment on 
>this aspect of the design if they had wished to, and they did not. 

If WebOnt accepts this response (the absence of discussion
in the last two days does not suggest otherwise), then the only option
from the list I made earlier would be to execute
the following, described in [1], which I repeat:

>*Possible solution 1*: no changes to RDF Semantics, and two
>"local" changes to S&AS:
>-1a: add OWL DL semantics without XMLLiteral by means of a
>detour via the abstract syntax (details below)
>-1b: exclude the possibility of having OWL Full without
>XMLLiteral semantics (after all, OWL Full is *OWL Full*)
>
>In view of 1b, this would not solve the problem completely, but
>perhaps this would be acceptable?
>In addition, 1b would require a small change in OWL Reference.
Actually, 1b does not describe a change in S&AS, since S&AS as it
is does already include XMLLiteral semantics in OWL Full.
However, 1b does lead to changes to make Test consistent.
For clarity, I list the other change required when this
solution is taken:
-1c: remove all tests that allow OWL Full without XMLLiteral
semantics

=

Pat made another remark that suggests that there is also 
another option to adapt the OWL documents to solve the problem:

PatH>The actual OWL design is that which is 
>described in the documents. If someone misunderstands these documents 
>then the appropriate course of action is for them to improve their 
>understanding.

In line with RDF Semantics, S&AS specifies OWL DL as well as OWL Full
to incorporate XMLLiteral semantics.
There are tests that state otherwise.
However, Test is secondary to S&AS. 
This leads to the following option for correction of the
S&AS documents (numbers 2 and 3 were already used):

*Possible Solution 4*:
-4a: add the requirement in Section 3 of S&AS that datatype maps
include XMLLiteral
(This change is suggested in part for clarity: it does not change
any entailments for OWL DL and OWL Full.
This change does remove the currently present third OWL semantics
in S&AS - abstract syntax-based semantics without XMLLiteral -
which should not be there because the WG decision on semantic
layering prescribes only two semantics, OWL DL and OWL Full.)
-4b: remove all tests that allow OWL Full or OWL DL without XMLLiteral
semantics

Not doing Solution 4 would be to change the design of OWL -
following what I cite above from Pat.
There is something to be said to follow RDF Semantics on this
issue - whatever choice is made in RDF Semantics.


[1] http://lists.w3.org/Archives/Public/www-webont-wg/2003Dec/0042.html
> 

Herman
Received on Friday, 12 December 2003 14:57:59 GMT

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