----- Original Message -----

From: Richard H. McCullough

To: KR-language

Cc: Larry Lefkowitz ; John De Oliveira

Sent: Tuesday, February 20, 2007 3:17 AM

Subject: [KR-language] Cyc father, mother

The translation of "subClassOf" is "iss*".
However, I have been "approximating" the meaning of
x iss* y;
as
x iss y;
Backing up one step, I just translated "subClassOf" to "iss",
which I expect is correct about 99.99% of the time.
But when it's wrong ... wow!
myCyc.mkr has an infinite loop:
father iss biologicalFather;
biologicalFather iss father;
(Ditto for mother.)

The correct translation is
father iss* biologicalFather;
biologicalFather iss* father;
from which we conclude that
father is biologicalFather; # same class

Note that in mKR, the "is" verb is not symmetric.
The right-hand-side name becomes the default name
used for expressing propositions. If I ask the question
father isa* ?:
the answer is
biologicalFather
\ biologicalParents
...

One final note:
these infinite loops are automatically
detected using the mKE command
do check od loop done;

Question for Cyc developers:
Do you really want to "hide" this kind of equivalence
in your knowledge base?

P.S. I have just corrected myCyc.mkr.

Dick McCullough
knowledge := man do identify od existent done;
knowledge haspart proposition list;
http://mKRmKE.org/