[Attempto] Should I allow for non-monotonic reasoning?

[David Whitten]

Thank you Norbert for the attention to the error.
I will test more when you fix RACE to your specifications.

I request that you accept "is provably" in your syntax as it
appears to be legal, even if it is superfluous, and following
the Hiltz Principal of "Least Surprises" it would make ACE
accepting of a varied input. Perhaps with a warning that the
syntax is superfluous to help people writing ACE develop
a sense of what is minimally necessary.

Again, thank you for a great system. Perhaps you could
help those of us on the mailing list by presenting a small
portion of the code and explain how it is done ? This
would allow us to develop more knowledge about ACE
internal mechanisms.

David

On Tue, Aug 11, 2015 at 4:59 PM, Norbert E. Fuchs <fuchs at ifi.uzh.ch> wrote:

> David
>
> > On 11 Aug 2015, at 13:47 , David Whitten <whitten at netcom.com> wrote:
> >
> > I don't know what I have done wrong.
> >
> > I tried using the web interface for race, but don't know why (below)
> subset #1 (Mary) and set#2 (at least 1 woman) are included.
> > I had the axiom set:
> >
> > Every man is a human. Every woman is a human.
> > Mary is a human that is a woman. John is a human that is a man. Mack is
> a human.
> > if a human is not provably a woman then the human is a man.
>
> As it seems your axiom set contains some redundancy in axioms 1 and 4, and
> axioms 2 and 3. I would have written either
>
> Every man is a human. Every woman is a human.
> Mary is a woman. John is a man. Mack is a human.
> If a human is not provably a woman then the human is a man.
>
> or somewhat less general
>
> Mary is a human that is a woman. John is a human that is a man. Mack is a
> human.
> If a human is not provably a woman then the human is a man.
>
> But even with these simplifications you would not get the expected
> results. As it turns out RACE contains a bug: I did not apply some internal
> transformations to the negation-as-failure axioms that I apply to the other
> axioms. The is a result of adding the "odd fellow" negation-as-failure to
> an otherwise functioning system. I am working on this rather complex issue
> and will let you know when I will be done. Until that time I would like to
> thank you for exposing this bug.
>
> >
> > I had the query:
> >
> > ...
>
> > I thought maybe I needed to say "man is a human" and "woman is a human"
> can't occur at the same time (or at least is abnormal) to exclude Subset #1
> and Subset #2, but instead I get a syntax error:
> >
> > Axiom Set:
> > Every man is a human. Every woman is a human.
> > Mary is a human that is a woman. John is a human that is a man. Mack is
> a human.
> > if a human is not provably a woman and the human is not provably a man
> then the human is a man.
> > if a human is provably a woman and the human is provably a man then it
> is abnormal.
> > if a human is provably a man then the human is not a woman.
> > if a human is provably a woman then the human is not a man.
>
> The syntax error is not surprising since "is provably" does not exist in
> ACE since it is superfluous. There is no difference between "if a human is
> provably a woman" and "if a human is a woman".
>
> Best regards.
>
>    --- nef
>
>
>
>
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