Introduction to interstices and intersticial gaps

Models of PAWednesday, February 20, 20136:30 pmCUNY Graduate Center in room 4214.03.

Erez Shochat

Introduction to interstices and intersticial gaps

St. Francis College

Let M be a model of PA for which Th(M) is not Th(N) (N is the standard model). Then M has nonstandard definable elements. Let c be a non-definable element. The largest convex set which contains c and no definable elements is called the interstice around c. In this talk we discuss various properties of interstices. We also define intersticial gaps which are special subsets of interstices. We show that the set of the intersticial gaps which are contained in any given interstice of a countable arithmetically saturated model of PA is a dense linear order.

Posted by on February 8th, 2013