Re: soundness and semantics

(general agreement -- a few comments.)

> It seems to me that behind the "soundness" discussions, the "semantics"
> issue is re-emerging.  My understandsing is as follows:
> 
> 1. Interchange of rules and rule sets originally specified after
> different semantics is needed. Therefore, the possibility of RIF rules
> and rule sets with different semantics should be a requirement.

I understand you to be saying RIF will need to have different dialects,
each with its own semantics.  Are you thinking of 2-5 standard dialects
or more than 6?

And if more more than 6, so you see a way to keep this manageable?

> 2. Such an interchange is only possible if the original semantics of the
> rules and rule sets to be interchanged is specified. Therefore, the
> possibility to specify a semantics for a rule or rule set should be a
> requirement.

That only comes up if there were rulesets with the same syntax by
different semantics, right?  But that's only one approach: we could use
different syntax (eg different namespaces or different element names)
whereever we need different semantics.

I wrote about this in the notes from F2F1:

http://www.w3.org/2005/rules/wg/wiki/Semantics_Extensibility_Point

> 3. In most cases, the specification of a semantics for interchange
> purposes is only possible or meanningfull if this specification is
> simple enough (ie expressible in a few words, not in ten thousand of
> lines of code) and abstract enough ("abstract" being understood here as
> "factoring out some aspects").
> As a consequence, simple and abstract specifications of semantics for
> RIF rules and rule sets should be a requirement.
> 
> Widespread approaches for sinmple and abstract sapeciofications of
> semantics for rules and rule sets are as follows:
> 
> A. for deduction and normative rules:
> 
> A1. model theories (either Tarskian or non-Tarskian).
> A2. Proof calculus (without model theories, like eg in constructive
> logics).
> 
> B. for production and reactive rules:
> 
> B1. fixpoint of an immediate consequence function (over rule sets and
> facts).
> B2. conflict resolution function (together with fixpoint of an immediate
> consequence function).

Some of us may not be familiar with these.  Can you point us to some web
pages about them?   (maybe via the Wiki)

> 4. The notion of "sound" inferences from RIF rules and rule sets can,
> and I think should, be defined as: inferences after the specified
> semantics.

I think that's what I've been saying.   *shrug*   Sorry if somehow it
seemed different.

> Did I miss something? Hopfully, this note will help clarifying issues...

Yep.   Thanks.

     -- Sandro

Received on Thursday, 11 May 2006 12:44:05 UTC