Kobe Set Theory Seminar


Schedule


Note: the forthcoming seminar sessions will take place virtually. Please contact Francesco Parente for details on how to attend.
2020-10-07 13:30
Speaker:
Diego A. Mejía (Shizuoka University)
Title:
Preserving splitting families
Abstract:
We present a method to force splitting families that can be preserved by a large class of finite support iterations of ccc posets. As an application, we show how to force several cardinal characteristics of the continuum to be pairwise different. This is a joint work with Martin Goldstern, Jakob Kellner and Saharon Shelah.



Previous talks


2020-08-04 15:00
Speaker:
Sakai Hiroshi (Kobe University)
Title:
Posets of size κ which destroy stationary subsets of Pκ(λ)
Abstract:
We discuss the existence of posets of size κ which do not preserve stationary subsets of Pκ(λ). More precisely, the consistencies of the following statements will be discussed:
  1. Add(κ) destroys stationary subsets of Pκ(λ).
  2. There is an ω1-stationary preserving poset of size ω1 which is not (semi-)proper.

2020-07-28 15:00
Speaker:
Fuchino Sakae (Kobe University)
Title:
A/the (possible) solution of Continuum Problem and the existence of Laver generic large cardinal
Abstract:
https://fuchino.ddo.jp/talks/abstract-2020-07-28.pdf

2020-07-23 16:00
Speaker:
Fuchino Sakae (Kobe University)
Title:
A/the (possible) solution of the Continuum Problem
Abstract:
In this talk, I am going to reuse the slides of my recent talk in Wrocław, though I am going to modify/improve some details of the slides for my presentation in Kobe set theory seminar.

2020-07-16 16:00
Speaker:
Francesco Parente (Kobe University)
Title:
Some combinatorics of ultrafilters on Cohen and random algebras
Abstract:
I will present recent joint work with Jörg Brendle, concerning ultrafilters on complete Boolean algebras. In particular, I will focus on some consistency results about Tukey reducibility and the ultrafilter number. The main motivation is to understand and classify (not necessarily generic) ultrafilters on the algebras adjoining Cohen and random reals.

2020-07-07 15:00
Speaker:
Fuchino Sakae (Kobe University)
Title:
On algebraic and geometrical characterizations of linear mappings
Abstract:
Under ZF+AD any f : RmRn is a R-linear mapping if and only if f is additive. More generally under ZF any such f is R-linear if and only if it is additive and continuous. In my talk, I will address the question whether f as above is a R-linear mapping if f sends each line in Rm either to a point or to a line in Rn.

Last updated: 2020-08-04