RE: [UCR] RIF needs different reasoning methods

Sandro Hawke wrote:
> To help keep us on track for Phase 1, the charter gives us a limit
> (roughly Horn rules) on which features of each system we will cover.
> Within that limit, I'm not sure there are many questions about which
> systems to cover.

"Roughly Horn rules" seems to exclude 

- production rules (and ECA/reaction rules)
- nonmonotonic reasoning rules (for defaults and heuristics)

It seems to include:

- limited forms of constructive derivation rules (such as 
  SQL views without negation)
- limited forms of (normative) integrity rules/constraints 
  (such as certain SQL ASSERTION clauses)

Ian Horrocks wrote:
> If the RIF supports rules with different meanings (i.e., 
> where different behaviour of the consuming system is  
> expected), then clearly 
> they would need to be distinguished. I don't see anyone 
> disagreeing about that.

OK, then we agree on Francois' proposal to mark/annotate
the distinction between these different types of rules
(I think this was the main point of the debate, and not 
the issue of efficient proof theories).

-Gerd