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Re: Another try at subclass

From: Chris Welty <cawelty@gmail.com>
Date: Wed, 19 Dec 2007 02:15:37 +0100
Message-ID: <476870B9.6060205@gmail.com>
To: "Public-Rif-Wg (E-mail)" <public-rif-wg@w3.org>

[Hoping to grab those last few free cycles before people go away for the next 
two weeks]

At this point I have heard no objection to this proposal, so I will try to make 
it a little more precise and add the rif:type relation as well. Basically, Jos 
and Dave, I am hoping to hear from you by email that you would not object (I you 
can live with) the following amendment, which would live (I believe) in the RDF 
compatibility document:

rif:subClassOf rdfs:subproperty rdfs:subClassOf .

This plus the transitivity semantics given to by Michael already in BLD, should 
  addresses the concern regarding the relationship to rdfs:subClassOf.

Finally, I suggest that either:
rif:type owl:sameAs rdf:type
or we just use rdf:type

Note that this still requires the semantics to say:

For all elements eo, ec, es ∈ D, the following must hold:
mint(Iisa(eo, ec), Isub(ec,es))   ≤t   Iisa(eo, es)

(which is already in the semantics for #)

The other objection to having Rif:type and rif:subclassof is why do we even need 
it.  The answer there is that many people (in the WG) seem to want it and it 
definitely helps address our coverage requirement since they are part of *so 
many* rule languages.

I realize that this is not enough for agreement, but I hope it is enough to 
remove objections.



Dave Reynolds wrote:
> Chris Welty wrote:
>> </chair>
>> Back in August I proposed a "friendly amendment" for the 
>> rif:subClassOf relation (aka ##) saying that:
>> rif:subClassOf rdfs:subproperty rdfs:subClassOf .
>> Michael was not opposed, he thought that it was obvious.  Jos replied 
>> as below, indicating some possible softness on the point.  I don't 
>> think DaveR responded. But I didn't push on it as some other thing 
>> must have come up (like vacation probably), and the thread ended with 
>> Jos' message below.
> I think we discussed it briefly at a telecon.
>> So before we give up on it, because I do think it would be useful to 
>> have in BLD, I'd like to see if this will make a difference to anyone, 
>> specifically the objectors to having rif:subClassOf (DaveR, Jos, ?).
> I do think it helps a little.
> It doesn't answer the question of why we are creating this semi-parallel 
> set of concepts in the first place.
> However, it does address one of the sub-issues viz it helps us answer 
> the obvious question "so how do rif:type and rif:subClassOf related to 
> the similar sounding RDFS/OWL properties?". At a minimum if we put these 
> in BLD we need a clear answer to that question and this does that. Well 
> does half of it - would need a similar thing for rif:type (or whatever 
> the URI for # is).
> Dave

Dr. Christopher A. Welty                    IBM Watson Research Center
+1.914.784.7055                             19 Skyline Dr.
cawelty@gmail.com                           Hawthorne, NY 10532
Received on Wednesday, 19 December 2007 01:15:54 UTC

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