This Week in Logic at CUNY


Models of Peano Arithmetic
Monday, March 12, 2012 7:00 pm Room 4214-03
Professor Alfred Dolich (Kingsborough Community College)
The D’Auquino Knight Starchenko Theorem


Computational Logic Seminar
Time 2:00 – 4:00 PM, March 13, Room 3209.
Speaker: Yuri Gurevich, Microsoft Research
Title: Distributed Knowledge Authorization Language (DKAL): Managing
Policies and Trust

Abstract: With the advent of cloud computing, the necessity arises to
manage policies and trust automatically and efficiently. In a
brick-and-mortar (B&M) setting, clerks learn unwritten policies from
trustworthy peers. And if they don’t know a policy, they know whom to
ask. In the B&M-to-cloud transition, the clerks disappear. Policies
have to be explicit and managed automatically. The more challenging
problem yet is how to handle the interaction of the policies of
distrustful principals, especially in federated scenarios where there
is no central authority. The DKAL project was created to deal with
such problems. The new language, new logics and tools keep evolving.
We discuss the current state of the project.


Other New York Logic Events + Set Theory Seminar
Friday, March 16, 2012 12:00 pm TBA
Mr. Brent Cody (The Graduate Center of The City University of New York)
Some results on large cardinals and the continuum function

Abstract. The speaker will defend his dissertation.

Model Theory Seminar
Friday, March 16, 2012 12:30 pm GC 6417
Mr. Whanki Lee (CUNY Graduate Center)
Chronically resplendent models and totally resplendent models.

Logic Workshop
Friday, March 16, 2012 2:00 pm GC 6417
Professor Julia Knight (University of Notre Dame)
Integer parts for real closed exponential fields

Abstract. A real closed field is a model R of Th(ℜ). An integer part
for a real closed field R is a discrete ordered subring I such that
for all r in R, there exists i in I with i ≤ r < i+1. A real closed
exponential field is a model of a certain computably axiomatizable
fragment of Th(ℜ,2x). An exponential integer part is an integer part I
such that for positive i in I, 2i is in I. Mourgues and Ressayre
showed that every real closed field has an integer part. Ressayre
showed that every real closed exponential field R has an exponential
integer part. Ressayre’s construction is canonical once we fix a well
ordering of R and a residue field section (i.e., a maximal Archimedean
subfield). Each step of the construction seems effective. Even so,
there is an arithmetical real closed exponential field R, with an
arithmetical residue field section k and an arithmetical ordering < of
type ω+ω (R is low, and k and < are Δ30), such that Ressayre’s
construction of an exponential integer part is not completed in the
least admissible set.

This is joint work among Paola D’Aquino, Karen Lange, Salma Kuhlmann,
and the speaker.

– – – – Monday, Mar 19, 2012 – – – –

Models of Peano Arithmetic
Monday, March 19, 2012 7:00 pm Room 4214-03
Professor David Marker (University of Illinois at Chicago)
The Mourgues Rassayre Theorem


Model Theory Seminar
Friday, March 23, 2012 12:30 pm GC 6417
Professor Jouko Väänänen (University of Helsinki and University of Amsterdam)
On second-order model theory III

Abstract. This mini course will cover the following topics: second
order characterizable structures, Henkin models, Completeness Theorem,
internal categoricity, and existence of second order equivalent
non-isomorphic models.

Logic Workshop
Friday, March 23, 2012 2:00 pm GC 6417
Professor Curtis Franks (Department of Philosophy, University of Notre Dame)
Gödel’s last thought on Gentzen’s consistency proof

Abstract. A transcript of a series of conversations between Kurt Gödel
and Sue Toledo from the years 1972 to 1975 was recently made available
and published in Kennedy and Kossak 2011. Among the most striking
remarks recorded in these notes is Gödel’s claim that Hilbert’s
program “was completely refuted,” though by Gerhard Gentzen’s work
and not by Gödel’s own results. This is exactly opposite the customary
appraisal of these matters. Drawing from the details of Gödel’s late
thought and some basic technical observations, we can understand how
Gödel could make such a claim and begin to appreciate an attitude
towards foundations that differs greatly from familiar ideas.



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