I will present on the paper “Largest initial segments pointwise fixed by automorphisms of models of set theory” by Enayat, Kaufmann, and McKenzie.

https://arxiv.org/abs/1606.04002

Keller Hall 301

I will present on the paper “Largest initial segments pointwise fixed by automorphisms of models of set theory” by Enayat, Kaufmann, and McKenzie.

https://arxiv.org/abs/1606.04002

Keller Hall 301

“Iterated ultrapowers for the masses”, part 2

Comparing Near-linearity Notions in Open Induction

There have been works in number theory on characterizing the class of Beatty sequences (integer parts of natural multiples of a fixed nonnegative real slope). The same is true for the inhomogeneous case when a fixed intercept is added before taking the integer part. We consider some notions of multiplicative or additive near-linearity and elaborate on the extent to which they charecterize various such sequences. We show some implications from standard number theory carry over to Open Induction and some do not. [In a second talk we could relate this to the weak fragment allowing the standard integers as a direct summand of a model. That second talk would include two more multiplicative vs. additive topics, details to follow.]