- From: Sandro Hawke <sandro@w3.org>
- Date: Wed, 10 May 2006 23:36:29 -0400
- To: Chris Welty <cawelty@frontiernet.net>
- Cc: public-rif-wg@w3.org
> > I want it to be able to safely include the ruleset
> > containing both these rules and make inferences which will be sound,
> > even though it has no idea what the second rule is supposed to mean. It
> > will certainly be incomplete because of not knowing what the second rule
> > means, if it wasn't incomplete already.
> >
>
> Regardless of what Francois thinks "sound" means, this argument of yours
> above seems to make assumptions about monotonicty and negation. What if
> e.g. the rule you understand expresses a default and the rule you don't
> understand expresses an exception? You may draw a conclusion that is
> incorrect, i.e. unsound wrt the semantics of the unknown dialect.
I believe this is the same as the biggest issue at the workshop,
although in a slightly different form. The simpler form of this issue
comes up when the rules are in the same dialect but in different
rulesets. Can you merge rulesets? See
http://www.w3.org/2004/12/rules-ws/report/#negation-as-failure
That summary doesn't really do it justice. At the workshop this
conflict -- represented mostly by Benjamin Grosof and TimBL -- got to
the point of being funny. Everyone seemed to kind of settle on the idea
that "scoping" was the answer, but there wasn't a clear consensus on a
technical definition of scoping.
It came up again in chartering, mostly under the keyword "monotonicity",
eg in the thread around
http://lists.w3.org/Archives/Public/public-rule-workshop-discuss/2005Aug/0087
To put it in different terms, the requirement I'm proposing is a
requirement for many of our use cases, but yes, it conflicts with other
requirements. We need some clever solution. Several people (including
TimBL and Michael Kifer) have suggested they have solutions. I believe
I can represent Tim's solution (which is essentiall N3's log:notIncludes
predicate).
-- Sandro
Received on Thursday, 11 May 2006 03:36:45 UTC