Dear all,

The seminar meets on Wednesday October 10th at 11:00 in the Institute of

Mathematics CAS, Zitna 25, seminar room, 3rd floor, front building.

Note that there will be no seminar on Wednesday October 17th.

Program: Miha Habič — Surgery and generic coding

There has been some interest recently in nonamalgamability phenomena

between countable models of set theory, and forcing extensions of a

fixed model in particular. Nonamalgamability is typically achieved by

coding some forbidden object between a collection of models in such a

way that each model on its own remains oblivious, but some combination

of them can recover the forbidden information.

In this talk we will examine the problem of coding arbitrary information

into a generic filter, focusing on two particular examples. First, I

will present some results of joint work with Jonathan Verner where we

consider surgical modifications to Cohen reals and sets of indices where

such modifications are always possible. Later, I will discuss a recent

result of S. Friedman and Hathaway where they achieve, using different

coding, nonamalgamability between arbitrary countable models of set

theory of the same height.

Best,

David