Re: [RIF] [UCR]: What is the RIF (revisited) --> disjunctive conclusions

[Francois Bry]

Michael Kifer wrote:

>IMO, it would be preferable that integrity constraint can be expressed in RIF without having to be re-writen eg using the above-mentioned transformation.
>  
>


By the way, this transformation amounts to negation:

A => (B or C) |=| A & not (B or C) => false |=| not(A & not (B or C))

>I think we have a consensus that we should not tackle disjunctions in the
>heads of *deductive* rules in Phase 1.
>
I would prefer not to have such a restriction because it would preclude
a natural, ie non-encoded, representation of IC, and would prevent
handling negociations.

>Since we already discussed that RIF rulesets could be tagged with semantics
>to let the recipient understand the intended meaning, I don't see
>significant obstacles to allowing disjunctions in the heads of deductive
>rules when these are tagged with classical or stable-model semantics. The
>recipient engine can reject such rules, if it doesn't have an engine to
>process them.
>  
>
+1

Francois

[mmk]

Francois Bry <bry@...> wrote:
>
> Michael Kifer wrote:
>
> >IMO, it would be preferable that integrity constraint can be expressed
> >in RIF without having to be re-writen eg using the above-mentioned
> >transformation.
> >  

The attribution here is wrong. I didn't write the above.
But yes, this is what Lloyd-Topor is about.

>
>
> By the way, this transformation amounts to negation:
>
> A => (B or C) |=| A & not (B or C) => false |=| not(A & not (B or C))
>
> >I think we have a consensus that we should not tackle disjunctions in the
> >heads of *deductive* rules in Phase 1.
> >
> I would prefer not to have such a restriction because it would preclude
> a natural, ie non-encoded, representation of IC, and would prevent
> handling negociations.

Then we will not have phase 1 in the foreseeable future.


        --michael