ETAI Newsletter Actions and Change

ETAI Newsletter on
Reasoning about Actions and Change


Issue 97005 Editor: Erik Sandewall 30.9.1997

The ETAI is organized and published under the auspices of the
European Coordinating Committee for Artificial Intelligence (ECCAI).

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.