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Re: Meta-classes? (layered architecture)

From: pat hayes <phayes@ai.uwf.edu>
Date: Mon, 16 Oct 2000 13:05:26 -0500
Message-Id: <v04210106b610f1a45676@[205.160.76.86]>
To: Ian Horrocks <horrocks@cs.man.ac.uk>
Cc: www-rdf-logic@w3.org
>Firstly, my main point (with which I think Pat agrees) is that we
>should define a simple "base" language, and then extend it as
>necessary with -META -SECOND_ORDER or whatever.

Yep, I think everyone agrees with this, more or less.

>My particular worry was the potential confusion that is derived from
>building on top of RDFS, which is designed so as to be able to
>describe itself. For example, according to the specification,
>rdfs:Class is a type of rdfs:Class as well as being a subClassOf
>rdfs:Resource, which itself is a type of rdfs:Class. An rdf:Property
>is also a type of rdfs:Class.

Ah, I may have been misreading this.  Maybe it is my turn to 
demonstrate lamentable ignorance in public, but could you briefly 
explain what the distinction is between being a type of and being a 
subclass of? I assumed that the fact that rdfs:Class is a type of 
rdfs:Class means that classes are a kind of class, which seemed 
harmless since it is a tautology. (Perhaps I should understand the 
first occurrence of 'rdfs:Class' here to be a mention rather than a 
use?)

Pat Hayes

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Received on Monday, 16 October 2000 14:02:24 GMT

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