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Re: Feedback request

From: Frank Manola <fmanola@mitre.org>
Date: Fri, 01 Nov 2002 08:05:56 -0500
Message-ID: <3DC27C34.9010800@mitre.org>
To: Brian McBride <bwm@hplb.hpl.hp.com>
CC: pat hayes <phayes@ai.uwf.edu>, w3c-rdfcore-wg@w3.org, dan Brickley <danbri@w3.org>

Brian McBride wrote:

> 
> At 21:28 31/10/2002 -0600, pat hayes wrote:
> 
>> Quick request(s) for feedback. There are 5 parts to this message.
>>
>> Please say if you think that any of the following entailments should 
>> NOT be valid in RDF or RDFS, or have any problems with the reasoning 
>> sketched. Obviously "10" can be any string.
>>
>> 1. (RDF)
>> aaa ppp "10" .
>> -->
>> aaa ppp _:xxx .
>>
>> 2. (RDF)
>> aaa ppp "10"^^datatypefoo .
>> -->
>> aaa ppp _:xxx .
>>
>> 3. (RDF)
>> aaa ppp "10"@lang .
>> -->
>> aaa ppp _:xxx .
> 
> 
> Oh dear, I knew this would come up sometime.  This will get into the are 
> resources literals issue and pretty much allows literals as subjects:
> 
>   aaa ppp "10" .
>   aaa ppp _:l .
>   _:l rdfs:type rdf:Literal .
> 
> Blank nodes come from anonymous resources and a lot of folks, not all, 
> read M&S as Frank did that literals and resources are disjoint.  I'd 
> rather we stayed away from these, but I suspect its too late in that we 
> have test cases of this form, e.g. the tidy entailment.
> 
> 
>> From the above, and assuming bare literals denote themselves, then IR 
>> must contain all bare literals (cuzof 1) and all values that any 
>> datatype can map them into (cuzof 2) and maybe all pairs of all those 
>> things with lang tags (not yet sure about that last one). So we might 
>> as well say that IR contains all of LV, seems to me. In which case we 
>> would get
>>
>> 4. (RDFS)
>> rdfs:Literal rdfs:subClassOf rdf:Resource .
> 
> 
> Ha!


Concur with Brian's comments on the above.


> 
> 
>> 5. (RDFS)
>> aaa rdf:type rdfs:Datatype .
>> --->
>> aaa rdfs:subClassOf rdfs:Literal .

> 
> 
> I'm tempted not here as it gives us vocabularly to talk about the old 
> style literals.  Folks who wrote
> 
>   aaa rdfs:range rdf:Literal .
> 
> won't suddenly find that integers are now allowed as property values.  
> There again maybe they would want that.
> 
> This is the sort of question where I'd want to hear Danbri's judgement 
> as he has a good feel for how such changes might go down in various 
> sections of the community.


I assume the problem here isn't with the premise (aaa rdf:type 
rdfs:Datatype), because aaa here is a DT URI, but with the entailment. 
I also concur with Brian's comments (this is one of the reasons the 
Primer doesn't cover rdfs:Datatype and the declaration of datatypes
in schemas yet).


> 
> 
>> ------
>>
>> Terminology question: now we have lists, should the term 'container' 
>> be understood to include lists as well as seqs, bags and alts? If so, 
>> does anyone have an suggestion for a generic term for the older 
>> containers? (Simple containers? Open containers? Bushy containers?)
> 
> 
> Broken containers?  Leaky containers?
> 
> 
> I've been using the forms:
> 
>   Containers for the old style containers
>   Collections (based on the parseType term) for lists and explaining 
> that a collection is represented as a list structure.
> 
> But I'm not wedded to it.  I do need to know by next Thursday though, a 
> deadline for something else I'm writing.


This is the distinction I've sort of made in the Primer.  Bag, Alt, and 
Seq are "containers", and containers and collections are for 
representing "groups" of things.


> 
> 
>> ------
>>
>> Can anyone fill in the blank for
>>
>> rdfs:comment rdfs:range ??? .
> 
> 
> rdf:Literal
> 
> 
>> ------
>>
>> Er..sorry, I ought to know this, but I am honestly unable to recall 
>> where the hell we are now. Have we decided to NOT allow property 
>> datatyping, ie the use of a datatype URI as a property to link a node 
>> to a bare literal, with the datatype implication that the node denotes 
>> the resulting value? Or to ALLOW it? That is, should
>>
>> 6.
>> aaa ppp "10"^^datatypefoo .
>> --->
>> aaa ppp _:xxx .
>> _:xxx datatypefoo "10"
>>
>> or not? If so, how about the reverse entailment??
> 
> 
> My understanding is we took this out when we simplified datatyping back 
> in the summer.  I think the deal is that WE are not standardizing this 
> but a future WG likely will, so we don't do it now, but we also don't do 
> anything that would break it.


Agree.


> 
> 
>> ------
>>
>> Finally, here is my current take on the total RDF and RDFS namespaces. 
>> Please correct any errors or omissions. In particular, did we trash 
>> rdf:containerMembershipProperty?
>>
>> RDF:
>> rdf:type   rdf:Property
>> rdf:Statement rdf:subject rdf:predicate rdf:object
>> rdf:Seq rdf:Bag rdf:Alt rdf:_1 rdf:_2 ...
>> rdf:List rdf:first rdf:rest rdf:nil
>>
>> RDFS:
>> rdfs:domain rdfs:range rdfs:Resource rdfs:Literal rdfs:Class 
>> rdfs:subClassOf rdfs:subPropertyOf rdfs:member rdfs:Datatype
>> rdfs:seeAlso, rdfs:isDefinedBy, rdfs:comment  rdfs:label
>>
>> -----
>>
>> Thanks.
>>
>> Pat



-- 
Frank Manola                   The MITRE Corporation
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Received on Friday, 1 November 2002 07:53:39 EST

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