First Meeting of the Quarter Tomorrow

[Ryan Flannery]

Dear UC Logic & FOM,

This is just a reminder that the first presentation of the quarter
will be tomorrow, Wednesday 16 January, from 3:30 to 4:30pm in 807 Old
Chem. Professor John Schlipf (CS) will be presenting. Most likely,
his presentation will continue onto this Friday's
meeting (same time and place).

Abstract:
Various people have proposed methods of modifying formal logic to
describe ordinary discourse and ``common sense'' reasoning. One such
approach is John McCarthy's circumscription. There, the syntax is the
same as for classical logic, but the semantics is changed; only some
of the classical models of a formula are considered. We define
circumscription, in two of its variants, and discuss its motivation in
``negation as failure.'' McCarthy hoped that his ``common sense
reasoning'' would be computationally easier than classical logic.
Unfortunately, the opposite turns out normally to be true. We state
and sketch the proofs of some results.

See you tomorrow,
-Ryan