CLT@SU-AI.ARPA (03/09/84)
From: Carolyn Talcott <CLT@SU-AI.ARPA>
[Forwarded from the CSLI bboard by Laws@SRI-AI.]
Subject: SEMINAR IN LOGIC AND FOUNDATIONS OF MATHEMATICS
SPEAKER: Johan van Benthem, University of Groningen
TITLE: "From Completeness Results to Incompleteness
Results in Modal Logic"
TIME: Wednesday, Mar. 14, 4:15-5:30 PM
PLACE: Stanford Mathematics Dept. Room 383-N
For a long time the main activity in intensional logic
consisted in proving completeness theorems, matching some
logic with some modal class. In the early seventies,
however, various incompleteness phenomena were discovered -
e.g. such a match is not always possible. By now, we know that
the latter phenomenon is the rule rather than the exception,
and the issue of the `semantic power' of the possible worlds
approach has become a rather complex and intriguing one.
In this talk I will give a survey of the main trends in the
above area, concluding with some open questions and partial
answers. In particular, a new type of incompleteness theorem
will be presented, showing that a certain tense logic defies
semantic modelling even when both modal class and truth
definition are allowed to vary.