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Re: Bugs in 2000/12 daml+oil reference on DAML collections

From: Peter F. Patel-Schneider <pfps@research.bell-labs.com>
Date: Fri, 12 Jan 2001 13:09:41 -0500
To: horrocks@cs.man.ac.uk
Cc: www-rdf-logic@w3.org
Message-Id: <20010112130941E.pfps@research.bell-labs.com>
There appears to be a type problem in the definition of DAML+OIL lists.  

The problem is that there is no way of typing a list.  For example,
Disjoint could be a list of anything---not necessarily a list of classes,
as we want/require.  Note that this problem is not confined to DAML+OIL as
RDF(S) itself has no (decent) mechanism for constraining the type of
collection elements.

DAML+OIL has a bigger problem, however, in Disjoint.  Disjoint is a
subclass of List.  Does this mean that the rest of a Disjoint should also
be a Disjoint?  This seems to make sense, but it can't be as lists have to
be terminated by a nil, which is not a Disjoint, just a List.

peter
Received on Friday, 12 January 2001 13:10:03 GMT

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