Re: more closed-world chatter

From: Jon Heggland <jon.heggland_at_idi.ntnu.no>
Date: Mon, 07 May 2007 08:21:02 +0200
Message-ID: <f1mgjn$8t6$1@orkan.itea.ntnu.no>

Marshall wrote:
> So, there are a variety of possible answers. Bob
> for example considers this within the context of
> a type theory that has subtyping, whereas Jon
> proposes a type mismatch. Both answers have
> their merits. Another question: what is the type
> of that attribute in the result relation? Possible
> answers include the top of the type lattice and

The most specific common supertype, I'd say (parroting D&D, as usual:). Which might be the top, of course, but not necessarily.

> the bottom; I am inclined to prefer the bottom.

Are you familiar with TTM's IM prescription 13: Join etc. with inheritance? Are you able to reconcile your preference with that?

-- 
Jon

Received on Mon May 07 2007 - 01:21:02 CDT