[sc34wg3] Re: [tmcl-wg] Type versus Class: settled yet?

[Lars Marius Garshol]

* Mary Nishikawa
|
| Actually, I think we still need to come to grips with these. In
| Barcelona, we decided to replace the term "class" with "type."

So we did. This was issue 'type-vs-class'.

| So now we should be using the terms topic type, subtype, and
| supertype. While working on this draft, I found I really wanted to
| really use "class"not "type." I don't think they are interchangable
| in all cases.
| 
| Class of things is the set of things. Type of things is not, it is
| the category that describes the things in the set.

I can't say that I agree with this. You may be able to find an example
of someone using these two terms this way, but I don't think that this
is generally correct.

| So we usually say, what type or (kind) of ice cream is your
| favorite?  We do not say, what class of ice cream is your favorite.

This is colloquial use of the terms, not technical.

* Dan Brickley
|
| Hey, if you folks haven't picked names for these two relations yet,
| I hereby propose 'type' and 'subClassOf'; type relates an instance
| to a class it is a member of, while subClassOf is a relation between
| classes.  FWIW these are the terms we use in RDF/S and OWL.

I discussed this very briefly with Dan a couple of days ago:

Mar 21 20:11:51 <danbri>	lars, some thread i sorta started on
                                one of the tm lists just lurched back 
                                into life... 
Mar 21 20:11:56 <danbri>	i've forgotten most of the context
Mar 21 20:12:18 <danbri>	i _think_ i was saying 'if you folks
                                have constructs with same semantics as 
                                rdf:type and rdfs:subClassOf, how
                                about using the same names?'
Mar 21 20:12:31 <larsbot>	danbri: that's a strange thing to have 
                                been saying
Mar 21 20:12:54 <danbri>	is it? oh dear!
Mar 21 20:13:05 <larsbot>	"we call it 'type' and 'class' 
                                interchangeably. could you please be
                                as inconsistent as us?" :-)
Mar 21 20:13:10 <danbri>	ppl were arguing about names
Mar 21 20:13:13 <danbri>	isa etc
Mar 21 20:13:21 <danbri>	yeah, fair point
Mar 21 20:13:27 <danbri>	a things type is a class
Mar 21 20:13:41 <larsbot>	we decided to just call it "type" and
                                leave "class" undefined
Mar 21 20:13:46 <danbri>	fair enough

(I'm quoting my IRC client logs, since I'm not online as I write
this.)
 
| It would be good if we came to some agreement on the use and try
| make sure that these are crystal clear.  So I am asking you to look
| at these definitions in RDF/S and OWL and comment on it. The
| definitions are not clearly defined (as far as I can see) but we
| need to do so ASAP. It very important for the TMCL.

I think what we should do is go with the Barcelona decision: we call
it type, and that's that. SAM has a simple definition of that notion
and I'm not sure we need to do anything more than that.

-- 
Lars Marius Garshol, Ontopian         <URL: http://www.ontopia.net >
GSM: +47 98 21 55 50                  <URL: http://www.garshol.priv.no >