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

Uli Sattler wrote:

>On 8 Feb 2006, at 11:49, Francois Bry wrote:
>
>  
>
>>Peter has been right to state the following, I think:
>>
>>a. RIF should have a formal syntax.
>>b. RIF should have a formal semantics.
>>
>>    
>>
>
>what is formal? Why not "well-defined" in the sense "If you give me a  
>set of rules, I can see what you meant by them, eg, which are its  
>consequences" -- what I do with them is, of course, up to me. For  
>example, I can use them with a different semantics.
>  
>
I used "formal" and not "weel-defined" bewcause UML's folk would argue 
that UML (informal) semantics is well-defined. With formal, I mean 
specified with widespread mathematical methods. IMO, a good semantics 
for RIF should be in form of Tarskian models.

>  
>
>>IMO, the following can be added:
>>
>>1. RIF's formal semantics might, and may be should, be more  
>>abstract than those of existing processable rule languages. Eg  
>>making it possible to express "negation as failure" without  
>>choosing between Stable Model and Well-Founded semsntics.
>>
>>    
>>
>but this choice will make a difference, and thus not explicating it  
>might lead to confusion! E.g., if I have a set of rules which reflect  
>some piece of knowledge, and I want to "sell" it to you, you need to  
>know how to read these rules: otherwise, you might draw conclusions  
>that should not be drawn or you might not draw conclusions that  
>should be drawn...
>  
>
What mean "should" not? Interchange gives room to a recipient to use 
data/knowledge in a different manner as intended by the sender. And 
often ewnough, this is very fruitful!

>I partly agree - but still, it would be useful to be able to describe  
>the "intended" reading of (a set of) rules -- even though we can then  
>use them in an un-intended way.
>  
>
I fully agree.

>  
>
>>My conclusion:
>>
>>Let us design a RIF with a formal language, a formal semantics  
>>leaving room for re-interpretations 9as examplefied above under 2  
>>and 3), and let us *not* define (or specify) a processor for RIF.
>>    
>>
>
>My conclusion:
>
>Let us design a RIF with a well-defined syntax and semantics which  
>allows us to describe the intended reading (ie, its consequences) of  
>a rule set -- whilst being open for re-interpretation. Please note  
>that "describing the intended reading" does not mean that we need to  
>specify a processor: to describe the reading of "\models" in first  
>order logic, we don't need to specify a theorem prover...
>  
>
I fully agree.

Francois

Received on Wednesday, 8 February 2006 12:25:30 UTC