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Re: review of Document Overview

From: Ian Horrocks <ian.horrocks@comlab.ox.ac.uk>
Date: Tue, 7 Apr 2009 16:40:04 +0100
Message-Id: <204AFA01-C650-4BB7-B8B0-4B927996F089@comlab.ox.ac.uk>
Cc: Sandro Hawke <sandro@w3.org>, W3C OWL Working Group <public-owl-wg@w3.org>, Peter Patel-Schneider <pfps@research.bell-labs.com>
To: Christine Golbreich <cgolbrei@gmail.com>
Thanks for that. I have updated the section in NF&R and added a  
suitable pointer to the Overview. IMHO this is all now in pretty good  
shape.

Ian


On 6 Apr 2009, at 23:22, Christine Golbreich wrote:

> I rapidly drafted something from bits of your texts (sorry but did not
> yet included Sandro's comments: have to recover it in the stack of
> emails)
>
> Here a possible  a pointer:
> http://www.w3.org/2007/OWL/wiki/ 
> New_Features_and_Rationale#Backward_Compatibility
>
> Any improvements or fixesr are welcome
>
> Christine
>
> 2009/4/6 Ian Horrocks <ian.horrocks@comlab.ox.ac.uk>:
>> As per your suggestion I removed the one sentence explanation of  
>> the meaning
>> of "to all intents and purposes", replacing it with a pointer to  
>> NF&R. This
>> will need to be fixed to a more precise reference to the location  
>> of the
>> relevant section when it has been added.
>>
>> I heard different opinions about Figure 2, so I didn't do anything  
>> on that
>> pending a decision from the WG. It seems slightly ridiculous for  
>> such a
>> minor issue, but I suggest that we put it on this weeks agenda for
>> discussion and disposition vote on it.
>>
>> Ian
>>
>>
>> On 3 Apr 2009, at 20:02, Sandro Hawke wrote:
>>
>>>
>>>>>>> 2.4/ Profiles:
>>>>
>>>>>>> Remove Figure 2, as it serves no useful purpose.
>>>>
>>>> I'm baffled as to what purpose you think this figure serves and why
>>>> its loss will be mourned. AFAICT, the information content of the
>>>> figure is:
>>>> ...
>>>
>>> It's not intended to provide additional information; it's about
>>> presentation.  It's intended to make the relationship between the
>>> profiles feel as simple as it actually is.  A simple-looking diagram
>>> conveys that feeling much more effectively, I think, than the text.
>>>
>>> But perhaps that's just me, so I'm okay with letting it go until/ 
>>> unless
>>> others speak up for it.
>>>
>>>>>>> Could remove the subsection headers, as the subsections are  
>>>>>>> all very
>>>>>>> short.
>>>>>>>
>>>>>>>
>>>>>>> Change "albeit under a possibly different name." to
>>>>>>>       "albeit possibly under different names."
>>>>>>>
>>>>>>> Remove "; it also has a formal equivalence to UML [UML]."
>>>>>>>       This is just *wrong*.
>>>>>>>
>>>>>>> 3.2:
>>>>>>>      Just put this stuff elsewhere (perhaps in Primer).
>>>>>>
>>>>>> I significantly shortened the whole of Section 3 and pointed  
>>>>>> to NF&R
>>>>>> for detailed explanation/documentation.
>>>>>>
>>>>>> I also renamed it "Relationship to OWL 1" as this seems more
>>>>>> appropriate and avoids the negative connotations of  
>>>>>> "differences".
>>>>>
>>>>> Very nice, except that we need a link explaining the "almost"s in
>>>>> paragraph two to a place with text like Peter and I were crafting
>>>>> yesterday.  If I were an OWL 2 user, I would insist the text
>>>>> actually be
>>>>> normative, too.  (I guess there's no problem with a little  
>>>>> normative
>>>>> text in NF&R.)
>>>>>
>>>>> Am I the only one who thinks OWL 1 users will want to know, in no
>>>>> uncertain terms, whether OWL 2 breaks their stuff, BEFORE they  
>>>>> accept
>>>>> OWL 2?
>>>>
>>>> This is *exactly* what I am trying to achieve here.
>>>>
>>>>> Figuring that out by sifting through our entire spec seems a bit
>>>>> much to ask.
>>>>
>>>> That isn't the intention. The intention is to tell them that
>>>> everything is fine, *which it is*. IMHO this message, we should  
>>>> *not*
>>>> provide irrelevant information about the corner cases and "bug- 
>>>> fixes"
>>>> in OWL 2 that prevent us from simply saying that it is *completely*
>>>> backwards compatible with OWL 1 -- this does need to be documented
>>>> somewhere, but not here (not sure if it should be normative and/ 
>>>> or in
>>>> NF&R, but this is a different issue that I will address in another
>>>> email).
>>>>
>>>> I changed what is said here to make the message even more clear: it
>>>> now says that "backwards compatibility with OWL 1 is, to all  
>>>> intents
>>>> and purposes, complete" and that inferences are identical "in all
>>>> practical cases". I also added a note explaining that "even the
>>>> theoretical possibility of different entailments arises only from a
>>>> change in the treatment of annotations in the Direct Semantics  
>>>> [OWL 2
>>>> Direct Semantics] that reflects what was typically implemented  
>>>> in OWL
>>>> 1 systems". I'm ambivalent about this note -- we could simply say
>>>> "see XXX for more details".
>>>
>>> Okay, yeah, I think this works.  I'd leave off the note and put a  
>>> link
>>> to the appropriate non-normative section of NF&R, so if people  
>>> want to
>>> double check whether they agree with our notion of "all intents and
>>> purposes" and "impractical", they easily can.
>>>
>>>> BTW, given that the differences in entailments only affect OWL  
>>>> DL and
>>>> derive from changes in the Direct Semantics, it seems to me that  
>>>> this
>>>> is the right place to document them.
>>>
>>> I'd lean towards having the change descriptions grouped together,  
>>> for
>>> those people who care about the changes.  In the future, hopefully,
>>> folks reading the OWL 2 DL specs wont care how it differed from  
>>> OWL 1
>>> DL.
>>>
>>>      -- Sandro
>>
>>
>>
>
>
>
> -- 
> Christine
Received on Tuesday, 7 April 2009 15:40:48 GMT

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