This Week in Logic at CUNY:

– – – – Monday, Feb 6, 2012 – – – –

– – – – Tuesday, Feb 7, 2012 – – – –

Computational Logic Seminar

Time 2:00 – 4:00 PM, February 7

Room 3209. NEW ROOM FOR THIS SEMESTER!

Speaker: Antonis Achilleos (Graduate Center)

Title: The complexity of multi-agent explicit knowledge.

Abstract: The purpose of the talk is to first give some background on the study of the complexity of justification logic and then proceed to present a family of multi-agent justification logics with

interactions. We will then analyse the complexity of some of the simpler cases of this family that are closely connected to the single-agent cases.

– – – – Wednesday, Feb 08, 2012 – – – –

– – – – Thursday, Feb 09, 2012 – – – –

– – – – Friday, Feb 10, 2012 – – – –

Set Theory Seminar

Friday, February 10, 2012 10:00 am GC 6417

Mr. Norman Perlmutter (CUNY Graduate Center)

Using iterated Prikry forcing to construct an inverse limit that is a proper subset of the thread set

Abstract. First, if necessary, I will finish up the development of the basics of iterated Prikry forcing from last week’s seminar. Next, I will review material on inverse limits of systems of elementary embeddings of models of set theory, which I first presented in the set theory seminar on October 14, 2011. Finally, I will apply an Easton/Gitik-support Prikry iteration to exhibit a system whose inverse limit exists but is a proper subset of the thread set. In other words, the inverse limit in the category of models of ZFC and elementary embeddings exists but is a proper subset of the inverse limit in the category of sets and set maps. The proof will take advantage of the fact that any tail of a Prikry iteration that does not begin at a limit point of the set of measurables being killed has a dense subset in the ground model. This allows for the iteration to be re-ordered as if it were a product.

Model Theory Seminar

Friday, February 10, 2012 12:30 pm GC 6417

Mr. Thomas Ferguson (Ph.D. Program in Philosophy, Graduate Center of CUNY) Model Theory for Many-Valued Logics, II: Ultraproducts and

Constructing Many-Valued Models

Abstract. In this session, some model theory for many-valued logics will be introduced. It will be shown how techniques such as Los’ Theorem may be extended to such logics and methods of constructing many-valued models from classical models will be introduced. Ultimately, we wish to show that ultraproducts “play nice” with such constructions by obeying some commutative properties.

Logic Workshop

Friday, February 10, 2012 2:00 pm GC 6417

Professor Roman Kossak (The City University of New York)

Open problems in models of Peano Arithmetic

Next Week in Logic at CUNY:

– – – – Monday, Feb 13, 2012 – – – –

– – – – Tuesday, Feb 14, 2012 – – – –

– – – – Wednesday, Feb 15, 2012 – – – –

Models of Peano Arithmetic

Wednesday, February 15, 2012 6:30 pm Room 4214-03 ((Note: new day and time))

Professor Roman Kossak (The City University of New York)

More on open problems in Models of PA

– – – – Thursday, Feb 16, 2012 – – – –

– – – – Friday, Feb 17, 2012 – – – –

Logic Workshop

Friday, February 17, 2012 2:00 pm GC 6417

Professor Philip Welch (University of Bristol)

Global Reflection Properties

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