Archives of: Prague Set Theory Seminar

Jonathan Verner: Coloring metric spaces

Dear all,

The seminar meets on Wednesday December 6th at 11:00 in the Institute of Mathematics CAS, Zitna 25, seminar room, 3rd floor, front building.

Program:
Jonathan Verner — Coloring metric spaces: A report from the oracle

“I will present a short and elegant argument, due to S. Shelah, showing how one can construct a metric space $X$ of size $2^\omega$ such that for any countable metric space  $K$ and any countable coloring of $X$ there is a monochromatic scaled copy of $K$ in $X$”.

David Chodounsky: A generalization of the Solovay–Tennenbaum theorem

Dear all,

The seminar meets on Wednesday November 29th at 11:00 in the Institute of Mathematics CAS, Zitna 25, seminar room, 3rd floor, front building.

Program:
David Chodounsky will present a generalization of the Solovay–Tennenbaum theorem; Assuming a diamond principle and given a suitable class PHI of ccc posets, there is a poset in the class PHI which forces MA(PHI) and c=kappa.

Šárka Stejskalová: Prikry-type forcings

Dear all,

The seminar meets on Wednesday November 15th at 11:00 in the Institute
of Mathematics CAS, Zitna 25, seminar room, 3rd floor, front building.

Program:
Šárka Stejskalová — Prikry-type forcings

Best,
David

Boriša Kuzeljević: Some applications of PID

Dear all,

The seminar meets on Wednesday November 8th at 11:00.

Program: Boriša Kuzeljević — Some applications of PID
The talk will be a continuation of the talk from the previous Wednesday.

Best,
David

Egbert Thümmel and Boriša Kuzeljević: the P-ideal dichotomy

Dear all,

The seminar meets on Wednesday November 1st at 11:00 in the Institute of
Mathematics CAS, Zitna 25, seminar room, 3rd floor, front building.

Program: Egbert Thümmel and Boriša Kuzeljević will review some classical
as well as new facts and applications of the P-ideal dichotomy (PID).

Best,
David

Jan Grebik: Borel selectors of Borel ideals (continued)

Dear all,

The seminar meets on Wednesday October 25th at 11:00 in the Institute of
Mathematics CAS, Zitna 25, seminar room, 3rd floor, front building.

Program: Jan Grebik — Borel selectors of Borel ideals (continued)
We present a result that there is an F_sigma ideal without Borel
selector and deduce that Galvin’s lemma does not have a “Borel proof.”
We also show that Nash-Williams theorem has a “Borel proof” and
therefore Galvin’s lemma is intrinsically more complex than
Nash-Williams theorem.

Best,
David

Jan Grebik: Borel selectors of Borel ideals

Dear all,

The seminar meets on Wednesday October 18th at 11:00 in the Institute of
Mathematics CAS, Zitna 25, seminar room, 3rd floor, front building.

Program: Jan Grebik — Borel selectors of Borel ideals
We present a result that there is an F_sigma ideal without Borel
selector and deduce that Galvin’s lemma does not have a “Borel proof.”
We also show that Nash-Williams theorem has a “Borel proof” and
therefore Galvin’s lemma is intrinsically more complex than
Nash-Williams theorem.

Best,
David

Saeed Ghasemi: Isomorphisms between reduced

Dear all,

The seminar meets on Wednesday October 11th at 11:00 in the Institute of
Mathematics CAS, Zitna 25, seminar room, 3rd floor, front building.

Program: Saeed Ghasemi — Isomorphisms between reduced
products of matrices

The talk will be mostly based on the paper:
https://arxiv.org/abs/1310.1353

Best,
David

Boriša Kuzeljević: P-ideal dichotomy and the strong form of the Souslin hypothesis

Dear all,

The seminar meets on Wednesday October 4th at 11:00 in the Institute of
Mathematics CAS, Zitna 25, seminar room, 3rd floor, front building.

Program:
Boriša Kuzeljević — P-ideal dichotomy and the strong form of the
Souslin hypothesis

Best,
David

Peter Vojtáš: Galois Tukey connections and reductions of (finite) combinatorial search problems

The seminar meets on Wednesday September 27th at 11:00 in the Institute
of Mathematics CAS, Zitna 25, seminar room, 3rd floor, front building.

Program:
Peter Vojtáš — Galois Tukey connections and reductions of (finite)
combinatorial search problems

We start from paper of A. Blass Query-Answer category … and present
some results and problems connected to K. Weihrauch reduction from
constru