From: Dan Connolly (connolly@w3.org)
Date: 10/16/00
[some of these questions/comments are starting to make my brain hurt, but some of them are easy. Rather than making the easy ones wait for the hard answers, I'll answer in parts...] pat hayes wrote: > > >pat hayes wrote: > > > > > > In DAML-ONT: > > > > > > </Property> <Property ID="disjointUnionOf"> > > > <label>disjointUnionOf</label> > > > <domain resource="#Class"/> > > > <range resource="#List"/> > > > <comment> > > > > > > for unionOf(X, Y) read: X is the disjoint union of the classes in > > > the list Y: (a) for any c1 and c2 in Y, disjointWith(c1, c2), > > > and (b) i.e. if something is in any of the classes in Y, it's > > > in X, and vice versa. > > > > > > cf OIL disjoint-covered > > > </comment> [...] > > > <! QUESTION: what is the value of your disjoint-union when the > >classes arent disjoint?> > > > >er... the same as the "value" of any other false assertion, > >such as 5<4. > > Nah, but your disjoint-union isn't an assertion, its an operator. Yes, it is an assertion. In what way is The class C is the disjoint union of the classes in the list L. not an assertion? > So > what its value is when its ill-defined is not so easy to specify. > Thats why I jumped on it, in fact: your definition is half assertion > (the arguments are disjoint) and half operator/function (like union > or intersection), so its neither fish nor fowl. One of the nice > things about the classical operations like disjoint-product is that > they are pure function, no assertion, so they always have a > well-defined value. > > ..... [...] -- bind default <http://www.w3.org/People/Connolly/kb> <mailto:connolly@w3.org> is mailbox of [a Person; called "Dan Connolly"; affiliation [ a Consortium; called "W3C"; homePage <http://www.w3.org> ]; homePage <http://www.w3.org/People/Connolly/>; officePhone <tel:+1-913-491-0501>; pager <mailto:connolly.pager@w3.org> ]
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