Re: [TED] Action-188, ISSUE: production rule systems have "difficulty" with recursive rules in RIF Core

> >[Core] is an intersection of all RIF dialects, not of all possible rule
> languages.
> 
> So if RIF-PR (aka the RIF dialect for PR) has no recursion, then
> recursion is not in the intersection, and thence recursion is not in
> Core?

RIF dialects are not the same as rule languages. Dialects will be selected
based on good criteria. Not having a recursion is unlikely to be judged as
a good criterion.


	--michael 

> 
> > What exactly do you mean by computational recursion?
> 
> I mean recursion used at compute-time (in execution), as opposed to
> recursion used in (logical) definitions. This may be moot / may or may
> not be useful! Please ignore if it isn't...
> 
> Paul Vincent
> TIBCO - ETG/Business Rules 
>  
> -----Original Message-----
> From: kifer@cs.sunysb.edu [mailto:kifer@cs.sunysb.edu] 
> Sent: 14 December 2006 17:53
> To: Paul Vincent
> Cc: Boley, Harold; Gary Hallmark; W3C RIF WG
> Subject: Re: [TED] Action-188, ISSUE: production rule systems have "difficulty" with recursive rules in RIF Core 
> 
> 
> > 	"This would be a ridiculous and unjustified restriction" 
> > unless CORE is meant to be a common subset of rule language features, in which case it is fully justified. If CORE is a superset of rule language features 
> th
> > en there is no need to consider extensions. So what is CORE?
> 
> It is an intersection of all RIF dialects, not of all possible rule languages.
> Otherwise we'll end up with relational algebra or even something smaller
> than that.
> 
> > 
> > From http://www.w3.org/2005/rules/wg/wiki/CORE <<... a format that allows rules to be translated between rule languages and thus transferred between rule s
> ys
> > tems. ... In Phase 1, the RIF Working Group is first defining a CORE Condition Language. These conditions are then used as rule bodies to define a CORE Hor
> n 
> > Language. >>
> 
> This formulation will need to be fixed. It is a leftover from F2F 3, I think.
> 
> > ... I take to mean that there no action language in Phase 1, so "computational recursion" is therefore anyway out of scope. 
> 
> What exactly do you mean by computational recursion? From the charter
> Phase 1 is supposed to include Horn with function symbols, so it would be
> computationally complete.
> 
> 
> 	--michael  
> 
> 
> > Paul Vincent
> > TIBCO - ETG/Business Rules 
> >  
> > 
> > -----Original Message-----
> > From: Boley, Harold [mailto:Harold.Boley@nrc-cnrc.gc.ca] 
> > Sent: 14 December 2006 15:34
> > To: Michael Kifer; Paul Vincent
> > Cc: Gary Hallmark; W3C RIF WG
> > Subject: RE: [TED] Action-188, ISSUE: production rule systems have "difficulty" with recursive rules in RIF Core 
> > 
> > Whether a *specific* Rulebase written in CORE uses recursion/co-recursion
> > or no recursion, can be found out by a static (dataflow) analysis system.
> > Keeping the result of this analysis for later use (including for production
> > rule transformation), e.g. in a 'semantic attribute', is a good example of
> > Rulebase-level annotations (cf. Roadmap, parts #6 and #9):
> > http://lists.w3.org/Archives/Public/public-rif-wg/2006Feb/0256.html
> > 
> > -- Harold
> > 
> > 
> > -----Original Message-----
> > From: public-rif-wg-request@w3.org [mailto:public-rif-wg-request@w3.org] On Behalf Of Michael Kifer
> > Sent: Thursday, December 14, 2006 10:55 AM
> > To: Paul Vincent
> > Cc: Gary Hallmark; W3C RIF WG
> > Subject: Re: [TED] Action-188, ISSUE: production rule systems have "difficulty" with recursive rules in RIF Core 
> > 
> > 
> > 
> > This would be a ridiculous and unjustified restriction.
> > 
> > The core is for exchange. There is no requirement for any concrete
> > system to properly include the core. (Don't confuse concrete systems with
> > RIF dialects.)
> > 
> > 
> > 	--michael  
> > 
> > > +1
> > > Recursion should not be a part of a core rule format (I'm pretty sure recursion is not a feature of constraint rules either).
> > > 
> > > Paul Vincent
> > > TIBCO - ETG/Business Rules 
> > >  
> > > -----Original Message-----
> > > From: public-rif-wg-request@w3.org [mailto:public-rif-wg-request@w3.org] On Behalf Of Gary Hallmark
> > > Sent: 13 December 2006 18:39
> > > To: public-rif-wg@w3.org
> > > Cc: W3C RIF WG
> > > Subject: Re: [TED] Action-188, ISSUE: production rule systems have "difficulty" with recursive rules in RIF Core
> > > 
> > > 
> > > 
> > > 
> > > Paul Vincent wrote:
> > > 
> > > >  
> > > >
> > > > Why would you want to define recursion 
> > > > (http://en.wikipedia.org/wiki/Recursion) in a production rule system?
> > > >
> > > >
> > > Paul,
> > > 
> > > As I understand it, RIF Core should be common to *all* RIF dialects, 
> > > including a production rule dialect.  Now, it's clear that there are 
> > > aspects of production rules that probably won't translate to Core (e.g. 
> > > priority, retract).  That may be ok if we can add them to the dialect 
> > > without breaking the Core semantics.  On the other hand, it is critical 
> > > that *everything* in Core can be translated to PR, otherwise we have 
> > > dialects of Core itself, which means it really isn't a Core.  Therefore, 
> > > if Core supports recursive rules, then so should PR.   If we don't think 
> > > its practical to support recursive rules in PR, then we should remove 
> > > this feature from Core.
> > > 
> > > Mark,
> > > 
> > > I agree that it may be more efficient to add new rete nodes and/or 
> > > syntax to support recursive rules, but that's not really the point.  The 
> > > translation from Core to PR should be possible (per our RIF 
> > > requirements) without having to modify or enhance the production rule 
> > > engine.
> > > 
> > > 
> > > 
> > > 
> > > 
> > 
> > 
> > 
> > 
> > 
> 
> 
> 
>

Received on Friday, 15 December 2006 10:50:44 UTC