# Re: NULLs: theoretical problems?

From: Keith H Duggar <duggar_at_alum.mit.edu>

Date: Sat, 01 Sep 2007 08:59:58 -0700

Message-ID: <1188662398.577820.259670_at_r29g2000hsg.googlegroups.com>

Date: Sat, 01 Sep 2007 08:59:58 -0700

Message-ID: <1188662398.577820.259670_at_r29g2000hsg.googlegroups.com>

Bob Badour wrote:

*> Keith Duggar wrote:
**>
**> > I'm not trying to have anything. I'm trying to understand what
**> > the "write DEF" prescription buys us over say the "Interactive
**> > Mathematical Proof System" of Farmer, Guttman, and Thayer that
**> > has exactly the property I described that any formula is false
**> > if any variable is NULL. Again, I am failing to grasp what the
**> > "write DEF" prescription buys us. I would like to understand.
**>
**> > KHD
**>
**> Error detection. It forces one to acknowledge that one understands the
**> attribute can be undefined and that one is ignoring those propositions
**> for which it is undefined.
*

**KHD
**
Received on Sat Sep 01 2007 - 17:59:58 CEST