********************************************************************
       ETAI NEWSLETTER ON  REASONING ABOUT ACTIONS AND CHANGE        
Issue 97005             Editor: Erik Sandewall             30.9.1997
Back issues available at http://www.ida.liu.se/ext/etai/actions/njl/
********************************************************************


                    *********  TODAY  *********


           ---  SEPTEMBER NEWS JOURNAL BEING ISSUED  ---

As already planned, the September News Journal contains the accumulated 
and slightly edited contents from the successive newsletters, for the
convenience of those who wish to look back at the discussion or 
other recent news in a coherent structure. It includes the material
up to and including the present Newsletter, and will be put on line
tomorrow following minor polishing.


                    *********  DEBATE  *********

  ---  DISCUSSION WITH WOLFGANG BIBEL ABOUT HIS IJCAI LECTURE  ---

Wolfgang Bibel's article is now reported to be available on-line, at
the following location. Visit
     http://aida.intellektik.informatik.th-darmstadt.de/~bibel/
where you find the following links
       Resume
       Group activities 
       Selected Publications 
       Projects 
Choose Selected Publications, with the IJCAI paper being the first one.


FROM: Wolfgang Bibel (answer to Pat Hayes)

> I'm surprised to read that any theorem-prover has solved the frame problem,

Where did you read this phrase? If I said so (which I hope I did not) then I
apologize for it. You are clearly right with:

> since the FP is a problem in representation, not in theorem-proving, and
> has nothing particularly to do with how deductions are processed.

> It is also rather surprising to read that some specialised logic has 
> solved the FP, since to do so its semantics would have to embody all 
> known and future causal laws.

How do you mean this sentence? Does, in analogy, the semantics of first-order
logic ``have to embody all known and future'' declarative knowledge?

> Could someone briefly explain how a better deductive search
> engine, or an exotic logic, can solve a problem in representation?

Why don't you read the respective parts of the paper. Again, at issue is a
logic not a search engine (although my paper does also connect the logic with
fol for which there is a great variety of search engines available). The logic
is equivalent with linear logic which you may have heard of before.

> On what might be a related matter, Bibel claims that ' deduction provides a
> generic problem solving mechanism ' (response to Friedman, ETAI 26.9.1997).
> Taken literally, this is clearly false, since deduction ...

The context makes it clear that ``deduction'' refers to an area of
research. It is indeed the goal of the deduction community to work out such
generic problem solving mechanisms.

>  ... itself provides no
> mechanism whatever: one only gets a mechanism when one chooses a strategy
> for performing deductions. For example, unification is not imposed by
> deduction; other strategies for instantiating universal variables are
> possible, computationally ridiculous but deductively perfectly valid. 

of course, of course


> So Bibel must be understood as referring not to 'deduction' per se, but to
> a particular deductive strategy, or class of deductive strategies. Perhaps
> in his original lecture (which I havnt yet got access to) he tells us which
> ones they are, but a brief summary would be helpful.

As I just said ``deduction'' refers to a field, a community.


********************************************************************
 This Newsletter is issued whenever there is new news, and is sent
 by automatic E-mail and without charge to a list of subscribers. 
 To obtain or change a subscription, please send mail to the editor,
 erisa@ida.liu.se. Contributions are welcomed to the same address.
 Instructions for contributors and other additional information is
 found at:   http://www.ida.liu.se/ext/etai/actions/njl/
********************************************************************