- From: Sandro Hawke <sandro@w3.org>
- Date: Thu, 11 May 2006 08:43:49 -0400
- To: Francois Bry <bry@ifi.lmu.de>
- Cc: Chris Welty <cawelty@frontiernet.net>, public-rif-wg@w3.org
(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