GROSOF@SUMEX-AIM.ARPA (05/06/84)
From: Benjamin Grosof <GROSOF@SUMEX-AIM.ARPA>
[Forwarded from the CSLI bboard by Laws@SRI-AI.]
Our regular meeting time and place is Wednesdays 1-2pm (with some
runover to be expected), in Redwood Hall Room G-19. [...]
Wednesday, May 16:
Drawing A Line Around Circumscription
David Etherington
University of British Columbia, Vancouver
The Artificial Intelligence community has been very interested in
the study of reasoning in situations where only incomplete information
is available. Predicate Circumscription and Domain Circumscription
provide tools for nonmonotonic reasoning in such situations.
However, not all of the problems which might be expected to yield to
circumscriptive inference are actually addressed by the techniques
which have been developed thus far.
We outline some unexpected areas where existing techniques are
insufficient.
Wednesday, May 23
DEFAULT REASONING AS CIRCUMSCRIPTION
A Translation of Default Logic into Circumscription
OR Maximizing Defaults Is Minimizing Predicates
Benjamin Grosof of Stanford
Much default reasoning can be formulated as circumscriptive. Using a revised
version [McCarthy 84] of circumscription [McCarthy 80], we propose a
translation scheme from default logic [Reiter 80] into circumscription. An
arbitrary "normal" default theory is translated into a corresponding
circumscription of a first-order theory. The method is extended to translating
"seminormal" default theories effectively, but is less satisfactorily concise
and elegant.
Providing a translation of seminormal default logic into circumscription
unifies two of the leading formal approaches to nonmonotonic reasoning, and
enables an integration of their demonstrated applications. The naturalness
of default logic provides a specification tool for representing default
reasoning within the framework of circumscription.