Re: Concrete types: next steps?

From: Jim Hendler (
Date: 02/05/01

>The operational difference appear, to me, to be two-fold:
>1/ Combination classes cannot be formed in Ian's and my approach.  That is,
>    you can't create the class of ``integers greater than 15 or people with
>    two brothers who are doctors''.
>2/ The only concrete classes that can be formed are those that are part of
>    the concrete type system (in this case XML Schema datatypes).  That is,
>    you can't create the class of integers who used to be the number of
>    employees of AT&T at the beginning of every month in the last year.
>My view (and I think that Ian and Deb would agree) is that these classes
>are not very useful, or at least that they can be avoided.  In particular,
>the second class would much better be modelled as a sequence of integers,
>not as a class of integers.  Even if you really want an unordered
>collection, an existential set (i.e., not an intensional class) appears to
>be a suitable choice.

OK, I'm beginning to get it -- but here's the issue, in my paper I describe the sort of 
application I want to do with the ontology language.  A key point is 
my being able to check whether inputs are legal within some defined 
range.  For example, I have a service with two parts.  First, it 
check to make sure that you enter a legal date in February of 2001 
(i.e. an integer between 1 and 28).  Then it checks to see if you 
enter a legal Credit card number (for now let's ignore format and say 
an integer between 0 and 999999999999999).

I realize I don't have to define a type to do this, but being a dumb 
C programmer it seems to me that that would be a good way to do it. 
Can you guys tell me how to do it correctly both in Peter/Ian and 
Dan's approaches?

(basically, I'm probing for a realistic use case to get this right - 
obviously a number from 1-28 can be easily handled as a sequence, but 
I worry about having to enumerate numbers in the trillions)


Prof. James Hendler
Computer Science Dept		703-696-2238 (phone)
Univ of Maryland		703-696-2201 (Fax)
College Park, MD 20853

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