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Re: Why do you want to do that?

From: Richard H. McCullough <rhm@pioneerca.com>
Date: Thu, 14 Aug 2008 11:54:44 -0700
Message-ID: <BECDCEFFA14145859E075ACC94F84AE5@rhm8200>
To: "Frank Manola" <fmanola@acm.org>
Cc: "Michael Schneider" <schneid@fzi.de>, "SWIG" <semantic-web@w3.org>, "KR-language" <KR-language@YahooGroups.com>

Hi Frank

Well, nobody ever asked me: "What do I want to do?"
Personally, I NEVER want to do it.
I will view X as an individual in one context,
and as a class in another context,
but I will NOT view X as an individual and a class in any context.

mKE will allow it, and has no trouble handling it.
But if you run the mKE consistency checks, including
    do check od unit done;
mKE will issue a warning message for every X which
is both an individual and a class.

Dick McCullough
Ayn Rand do speak od mKR done;
mKE do enhance od Real Intelligence done;
knowledge := man do identify od existent done;
knowledge haspart proposition list;
http://mKRmKE.org/

----- Original Message ----- 
From: "Frank Manola" <fmanola@acm.org>
To: "Richard H. McCullough" <rhm@pioneerca.com>
Cc: "Michael Schneider" <schneid@fzi.de>; "SWIG" <semantic-web@w3.org>; 
"KR-language" <KR-language@YahooGroups.com>
Sent: Thursday, August 14, 2008 8:34 AM
Subject: Re: Why do you want to do that?


> Dick--
>
> See below.
>
> On Aug 13, 2008, at 9:36 PM, Richard H. McCullough wrote:
>
>>
>> Hi Michael
>> See below.
>>
>> Dick McCullough
>> Ayn Rand do speak od mKR done;
>> mKE do enhance od Real Intelligence done;
>> knowledge := man do identify od existent done;
>> knowledge haspart proposition list;
>> http://mKRmKE.org/
>>
>> ----- Original Message ----- From: "Michael Schneider"  <schneid@fzi.de>
>> To: "Frank Manola" <fmanola@acm.org>
>> Cc: "SWIG" <semantic-web@w3.org>; "Richard H. McCullough" 
>> <rhm@PioneerCA.com
>> >
>> Sent: Wednesday, August 13, 2008 4:57 PM
>> Subject: RE: Why do you want to do that?
>>
>>
>>> Hi Frank!
>>>
>>> Frank Manola wrote:
>>>
>>>> There aren't any classes in RDF (per se);  in RDFS there are  classes,
>>>> and they can be treated as individuals (which is where we came in,
>>>> more or less).
>>>
>>> As a minor remark, I think it's easier to understand the situation of
>>> classes in RDFS, if one states the above sentence the other way  around: 
>>> In
>>> RDFS there are individuals (aka resources), and some of them can be 
>>> treated
>>> as classes, namely those which happen to have a class extension 
>>> associated
>>> with them. Analog, some individuals have a property extension 
>>> associated
>>> with them, and are therefore properties. An individual may even act  as 
>>> both,
>>> a class *and* a property, if it has both a class extension and a 
>>> property
>>> extension associated.
>>
>> But in any case (as you say), all classes and
>>> properties are individuals, which exist in the RDFS universe, i.e.  the
>>> domain of discourse.
>> ***** This is an unnecessary "corruption" of the concept hierarchy.
>> Once again, the simple alternative is to use sets.
>> all class ismem ClassSet;
>> all property ismem PropertySet;
>> all individual ismem IndividualSet;
>> Except for the last line above,
>> x being a member of a set does NOT make x an individual.
>
> This discussion seems to illustrate the meat of the matter.  Speaking 
> generally, it seems to me that, rather than treating properties and 
> classes as individuals being an unnecessary *corruption* of the  concept 
> hierarchy, *not* treating them as individuals is an  unnecessary 
> *simplification* of the concept hierarchy.  The key word  that applies, 
> though, is "sometimes".  The next line below seems to me  to say that you 
> want to be able to do that in some situations  ("contexts", if you must 
> use that word :-)   ).  That suggests that  your language/model must 
> support that capability (that is, if you  *ever* want to do that, the 
> capability must be there).  No one is  arguing that you need (or even 
> want) to be able to do that in all  situations (at least I'm not 
> so-arguing).  That people can  successfully use OWL-DL shows that this 
> capability is not needed all  the time.  But it's certainly useful to have 
> that ability in some  cases.  We couldn't even be having this discussion 
> without the ability  to treat classes and properties as individuals! 
> Recall that the  original question was "Why do you want to do that?"  I 
> think there  have been several examples of why given (including the one 
> you cite  below).  Dick, your argument now seems to be that you *never* 
> want to  do that *in the same situation*.  Is that so?
>
> --Frank
>
>>
>>
>> In an appropriate context, you might view a property as
>> an individual.  For example
>>   John Doe has happy;
>> But in other contexts, it seems better to view a property
>> as a Class.  For example
>>   John Doe has gender = male;
>> These examples correspond to the hierarchy fragment:
>>
>> begin hierarchy example;
>> Property;
>> /    i:happy;
>> /    gender;
>> //        i:male;
>> end hierarchy example;
>>>
>>>> That is, in RDFS a class is a resource (like
>>>> everything else that can be referred to in RDFS), and resources  can be
>>>> the subjects of triples.
>>>>
>>>> --Frank
>>>
>>> Cheers,
>>> Michael
>>>
>>
>>
>>
>
> 
Received on Thursday, 14 August 2008 18:55:44 GMT

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