Re: added diagrams to "Using XML Schema Data Types..."

From: Dan Connolly (
Date: 02/07/01

Jim Hendler wrote:
> At 12:40 PM -0600 2/7/01, Dan Connolly wrote:
> >
> >
> >To have the parsing of one document depend on the
> >contents of another conflicts with that goal/principle.
> >
> >Another way to state this principle is that
> >the knowledge contained in two documents, X and Y,
> >is always the conjunction of the knowledge in X with
> >the knowledge in Y. To allow X to change what Y says
> >in some non-monotonic way doesn't seem scalable/workable
> >to me.
> >
> I absolutely agree with the first of these and completely disagree
> with the second, so maybe they're not exactly equivalent... since I
> tend to like examples, here's one
> Web page 1 says:  X is true
> Web page 2 says:  X is False
> The parsing of web page 1 or two is not changed by reading the other,
> but I don't know a good monotonic way to combine these two without
> problem (solution is for me to tag them, or reject them, or something
> - but I need to be allowed to recognize conflict)

It seems to me that you do know how to combine them
monotonically: you take their conjunction. It's
pretty clear that when you look at the knowledge
from pages 1 and 2 together, you've got a contradiction;
but that's not an exception to the rule
	KB(page 1 + page 2) = KB(page 1) + KB(page 2).

> web page 1 says: 1 is an integer
> web page 2 says: 1 is a real
> web page 3 says: 1 is not an integer
> are these cases inherentely different?  I'm not sure,

not at all.

Dan Connolly, W3C
office: tel:+1-913-491-0501
  (put return phone number in from/subject)

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