RE: DAML+OIL (March 2001) released

> From: Dan Connolly [mailto:connolly@w3.org]
[...]
> I argued (with Tim) against splitting the domains; but
> tools like OILed require the split in order to do
> efficient reasoning, and while I eventually want to
> get beyond that requirement, the group agreed it's
> worth keeping for at least a little while longer;
> but we agreed to note that it's a stop-gap solution:
> 
>   [[[
>   RESOLVED: We will release an updated language release
>   incorporating the current proposal, acknowledge the outstanding
>   issues and concerns, and solicit feedback from the larger
>   community.
>   ]]]
[...]

It's worth thinking about what happens if the split is removed, though.  In
particular, how does one avoid being able to express:

- 5 is a kind of -3;

- concrete class X is a kind of datatype D;

- The datatypes ["A", "N") and {"Aardvark", 1, 3.14159} are equal;

- refinements of data values ("the 3 which is the number of legs on a
3-legged pig"*) and what happens if you try to use the data values' built-in
predicates, such as less-than and greater-than.  For example, is "the 3
which is the number of legs on a 3-legged pig" greater-than "the 1 which is
the number of legs on half a pair of trousers"*?

Or does one simply define such concepts as incoherent?

		- Peter

* Both with apologies to Les Barker (http://www.mrsackroyd.com).