Re: CG: Re: SUO: Sowa's piece and thoughts on tractability
Quoting "John F. Sowa" <sowa@bestweb.net>:
> Erik,
>
> I strongly believe in the importance of analyzing the computational
> complexity of various kinds of problems and the algorithms used to
> deal with them. But I strongly disagree with the following statement:
>
> > One of the things I've faced in my own development efforts and in
> > thinking about effective representational schemes for AI
> applications
> > is the tradeoff between computational tractability and
> > representational expressivity.
>
> This fallacy results from a common misunderstanding. People observe
> that problems stated in a more expressive language A are sometimes
> more
> complex than problems stated in a less expressive language B.
> Therefore,
> they try to solve the complexity problems by forcing people to use B
> rather than A.
This is the line the CG community has been pushing for many years and I am here
to continue pushing it. Research as much as you want into sublanguages and build
specialist subsumption, unification, reasoning algorithms (this is all good
stuff, and we do make use of it) as much as you want, but please use an
expressive (hopefully standardised) representation so you are not limited to
those techniques.
People can cope with programming languages that have the power to write
programs that do not terminate, but still survive.
while (true) { }
There are automated techniques for detection of non-termination, though not
necessarily fool proof, there are others which can check for termination.
Identification of terms which have poly-subsumption etc can in many cases also
be identified using poly techniques. If it is a poly-term use the specialist
poly-algorithm, otherwise use the general technique (with your general
knowledge rep).
Cheers, Gerard.
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