RE: [RIF] [UCR]: What is the RIF (revisited)

> What might well be "more conventional semantics"? There are 
> two kinds of 
> model theories used for formalizing the declarative (ie 
> non-procedural) semantics of programming/rule languages:
> 
> 1. ad hoc definitons fo models eg well-founded and stable model 
> semantics. I agree that they are not easy to understand.

I would not call the stable model semantics an "ad hoc
definition", and I would not call the "well-founded
semantics" to be a model-theoretic semantics at all
(rather it is a proof theory, which is sound with
respect to the stable model semantics).

The stable model semantics (unlike the well-founded
semantics) can be considered a Tarski-style model-theoretic
semantics, because it is based on the Tarskian concept of
a model. It departs from the standard Tarski semantics
in not accepting all models as intended, but only the
stable ones which are supported by rules (following 
the basic intuition of minimal model semantics). This
departure is rather natural for a semantics of 
information and knowledge - as opposed to a semantics
of theorems (aspiring for eternal truth).

> 2. Tarskian model theories, ie the valuation (= truth value) of a 
> formula is recursively defined on the structure of the formula. Such 
> model theories are intuitive and much easier to understand than other 
> formalisms unsed in formalazing the "meaning" of programs.

I'm not so sure if the "direct model-theoretic semantics" 
of OWL is easier to understand than stable model semantics.
We should make a test...

-Gerd

Received on Saturday, 11 February 2006 01:51:08 UTC