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Re: Fwd: daml:item

From: Jeremy Carroll <jjc@hplb.hpl.hp.com>
Date: Fri, 20 Jun 2003 09:31:47 +0100
Message-ID: <3EF2C673.2000308@hplb.hpl.hp.com>
To: Jim Hendler <hendler@cs.umd.edu>
CC: webont <www-webont-wg@w3.org>


If we were to add this it would be an OWL Full feature, since OWL DL and 
OWL Lite do not permit the use of the RDF list vocabulary except in OWL 
built-in constructs (like interesectionOf).

Hence, I am less than convinced that we have adequately met DAML-S 
requirements on lists, at all; but then they should have made a comment to 
that effect. If Bijan wants a typed list then he wants OWL Full, or he 
wants us to make a biggish change.

Jeremy


Jim Hendler wrote:

> 
> Bijan Parsia raised the issue of whether OWL should include something 
> similar to the daml:item feature for compatibility.  We decided that 
> this was handled under issue 5.5, by (essentially) passing the buck -- 
> i.e. saying RDF Core decided to remove these and that we saw no reason 
> to add an owl:item.   I discussed this with him, and he sent me the 
> following - pointing out that while there is a work around, there is a 
> case (putting restrictions on all members of a list) that is easier with 
> daml:item.
>  Does this present new information that tempts anyone to request 
> re-opening of issue 5.5 and consideration of adding this feature?
>  -JH
> p.s. please note that he uses a case from daml-s, and he is currently a 
> member of the web services description WG, working on helping them with 
> their need to produce a mapping to RDF (which he is proposing to do at 
> least in part via OWL) using DAML-S, so this is more than a casual 
> observation.
> 
> 
>> Date: Thu, 19 Jun 2003 14:11:59 -0400
>> Subject: daml:item
>> From: Bijan Parsia <bparsia@isr.umd.edu>
>> To: hendler@cs.umd.edu
>> X-Spam-Status: No, hits=-9.5 required=5.0
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>>
>> One common use of daml:item is to make typed lists, say, a list that 
>> can only contain ex:Person (this actually pops up quite a bit in 
>> DAML-S). You put a restriction on daml:item to the desired class. This 
>> is just syntactic sugar as it can be expressed as a pair of 
>> restrictions on daml:first and daml:rest (or their rdf equivalents). 
>> (Note, at one point I thought this wasn't true because of daml:nil, 
>> but Peter claimed that daml:nil is compatible with every list type.) I 
>> think there are probably other use cases, but don't have any off hand.
>>
>> So, DAML+OIL compatibility isn't merely a matter of deleting 
>> daml:items. It's a feasible conversion, but it makes a lot of 
>> authoring uglier and some modeling conceptually harder to explain.
>>
>> Cheers,
>> Bijan.
>>
Received on Friday, 20 June 2003 04:32:17 GMT

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