Re: Prototypes

Fritz Lehmann (fritz@cyc.com)
Tue, 16 Dec 1997 12:26:16 -0600 (CST)

On Tue, 16 Dec 1997, John McCarthy wrote:
>[...]
> 5. HPKB and other projects need to tolerate loose ontologies, i.e. use
> necessary conditions and sufficient conditions without supposing that
> necessary and sufficient conditions are to be had.

Dear John McCarthy,

Agreed. I'd just like to add that all three combinations are often useful
for the same concept: It's often good to have necessary (inheritable),
sufficient (classifying), and necessary-and-sufficient (definitional)
formulae, facts and rules, all for the same concept. The three sets of
formulae can be quite independent of one another.

Yours truly, Fritz Lehmann

Fritz Lehmann, Cycorp, 3721 Executive Center Dr., Austin, TX 78731
fritz@cyc.com tel.: +1 (512) 342-4013 fax: +1 (512) 342-4040
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