**Computational Logic Seminar**

** Tuesday, March 12, 2013 12:01 am**

Speaker: Hitoshi Omori Kobe University, Visiting Fellow, Grad Center, CUNY

Title: Expanding the realm of the idea of da Costa

Non-classical logics that deny ex falso quod libet are said to be

paraconsistent. Since the monumental work of Stanislaw Jaskowski in

1948, a large number of paraconsistent systems have been developed.

Those include systems of da Costa, Nelson, Belnap-Dunn, Priest, Batens

and Scotch-Jennings. In this talk, we focus on the consistency

operator which is the characteristic connective of da Costa’s systems.

We understand that the main idea of da Costa is to make explicit,

within the system, the area in which you can infer classically. The

aim of the talk is twofold. First, we review some of the results

within the framework of Logics of Formal Inconsistency. Then, we

introduce and present some results on normality operator which

generalizes consistency operator so that one can deal not only with

inconsistency, but also with incompleteness. Second, we show that the

normality operator may be employed, in a sense to be specified, in

developing other paraconsistent logics such as modal logics, Nelson’s

systems and expansions of the four-valued logic of Belnap and Dunn.

**Models of PA**

** Wednesday, March 13, 2013 6:45 pm**

Speaker: Tin Lok Wong Ghent University

Title: Generalizing the notion of interstices

I will present a generalization of the notion of interstices that

originated from the study of generic cuts.

Set theory seminar

Friday, March 15, 2013 10:00 am

Speaker: Miha Habic

Title: Martin’s Axiom

Martin’s Axiom is the prototypical forcing axiom, asserting that

partial generics exist for ccc forcing. I will present the classical

proof of its consistency, due to Solovay and Tennenbaum. If time

permits I will also describe some of the consequences of Martin’s

Axiom, in particular its effect on the cardinal characteristics of the

continuum.

**Model theory seminar**

** Friday, March 15, 2013 12:30 pm**Philipp Rothmaler

Speaker: Philipp Rothmaler The City University of New York

Title: Stability revisited

I will discuss an observation Ivo Herzog and I made in the last

millennium that yields a purely topological definition of stability of

a complete first-order theory in terms of their Stone spaces.

**CUNY Logic Workshop**

** Friday, March 15, 2013 2:00 pm**

Speaker: Charles Steinhorn Vassar College

Title: Some approaches to model theory for classes of finite structures

This talk surveys work on the development of model theory for classes

of finite structures due primarily to Macpherson and the speaker, and

to several of Macpherson’s students. The underlying theme of this work

has been to bring to the model-theoretic study of classes of finite

structures aspects of the model theory of infinite structures.