Joint Prague-Vienna workshop in Set Theory and Logic (29.9.-2.10.)

There will be a joint meeting between the logic groups in Prague and Vienna starting on Monday, Sep 29 and ending on Thursday, Oct 1. The meeting will take place at the Institute of Mathematics of the Czech Academy of Sciences. Anyone who is around is welcome to participate. The program of the meeting will be announced shortly before the actual meeting. We expect the following people to attend (at least part of) the meeting:

  • Bohuslav Balcar
  • Barnabas Farkas
  • Sy Friedman
  • Martin Goldstern
  • Jan Grebík
  • Stefan Hoffelner
  • Radek Honzík
  • David Chodounský
  • Wieslaw Kubis
  • Wei Li
  • Diego Mejia
  • Diana Montoya
  • Petr Simon
  • Jan Starý
  • Šárka Stejskalová
  • Anda Tanasie
  • Egbert Thuemmel
  • Tin Lok Wong
  • Jonathan Verner

Mike Pawliuk: Various types of products of Fraisse Classes, various types of amenability and various types of preservation results

22 August 2014, 13:30–15:00

Fields institute, Room 210

Speaker:  Mike Pawliuk

Title:  Various types of products of Fraisse Classes, various types of amenability and various types of preservation results.

Abstract:

This is joint work with Miodrag Sokic. In a recent paper of Jakub Jasiński, Claude Laflamme, Lionel Nguyen Van Thé and Robert Woodrow (Arxiv: 1310.6466) it was shown that certain Fraisse Classes are actually Ramsey classes. For many of those cases we have determined whether their automorphism groups are extremely amenable or not. Some of these spaces turn out to actually be a special type of product of Fraisse classes. We were able to prove that unique ergodicity (a type of amenability) is preserved under this type of product.

Dilip Raghavan: On embedding certain partial orders into the P-points under Tukey and RK reducibility.

Invitation to the Logic Seminar at the National University of Singapore

Date: Wednesday, 20 August 2014, 17:00 hrs

Room: S17#04-04, Department of Mathematics, NUS

Speaker: Dilip Raghavan

Title: On embedding certain partial orders into the P-points under Tukey
and RK reducibility.

URL: http://www.comp.nus.edu.sg/~fstephan/logicseminar.html

The study of the global structure of the P-points was initiated
mainly by Blass in 1970s. In a paper in 1973 he asked what partially
ordered sets can be embedded into the P-points under the ordering of
Rudin-Keisler reducibility. This question is of most interest under some
hypothesis that guarantees the existence of many P-points, such as Martin’s
axiom for sigma-centered posets. In the 1973 paper he showed under this
assumption that both omega_1 and the reals can be embedded. This
result was later generalized to the coarser notion Tukey reducibility.
We will prove that under Martin’s axiom for sigma-centered posets
P(omega)/FIN can be embedded into the P-points both under Rudin-Keisler
and Tukey reducibilities. Since P(omega)/FIN is universal for partial
orders of size at most continuum, this a good step towards giving a
complete answer to Blass’ original question.

This is joint work with Saharon Shelah.

Omer Ben-Neria: The failure of diamond at large cardinals and GCH

Friday Set Theory Seminar (HUJI)
We shall meet this Friday (August 22nd) in the Hebrew University math department building, at 10 am.Speaker: Omer Ben-Neria (TAU)Title: The failure of diamond at large cardinals and GCH

Abstract: We establish the consistency of GCH together with the failure of
the diamond principle at large cardinal kappa, for kappa which is inaccessible, Mahlo, or weakly compact cardinal.

Frank Stephan: The complexity of verbal and pattern languages over groups

Invitation to the Logic Seminar at the National University of Singapore

Date: Wednesday, 13 August 2014, 17:00 hrs

Room: S17#04-05, Department of Mathematics, NUS

Speaker: Frank Stephan

Title: The complexity of verbal and pattern languages over groups

URL: http://www.comp.nus.edu.sg/~fstephan/logicseminar.html

Note: This meeting includes a short organisatorial session for organising
the logic seminar in this semester; in the case that you want to speak but
cannot come, please drop an email to Frank Stephan at fstephan@comp.nus.edu.sg.

Abstract:
The talk presents the complexity of verbal languages and pattern
languages of Thurston automatic groups in terms of the Chomsky hierarchy.
Here the language generated by a pattern is taken as the set of
representatives of all strings obtained when chosing values for the
various variables. For noncommutative free groups,
it is shown that the complexity of the verbal and pattern languages
(in terms of level on the Chomsky hierarchy) does not depend on the
Thurston automatic representation, that verbal languages cannot
be context-free (unless they are either the empty word or the full group)
and that pattern languages cannot be regular (unless they are either a
singleton or the full group). Verbal languages and pattern languages can,
however, be indexed languages.
Furthermore, it is shown that in the general case, it might depend on
the exactly chosen Thurston automatic representation which level a
verbal language takes in the Chomsky hierarchy. There are
examples of groups where, in an appropriate representation, all pattern
languages are regular or context-free, respectively.

Joint Work: This is joint work with Sanjay Jain and Alexei Miasnikov; the
talk builds on and extends work presented at LICS 2012.

Tom Pazak: Bell’s construction of topological spaces

Wednesday, August 13, 2014, 11:00
Prague – CTS

Speaker: Tom Pazak

Title: Bell’s construction of topological spaces

Seminar guest: Frantisek Franek

Menachem Magidor: Inner models constructed from generalized logics

Dear all,

We shall meet next Friday (August 15th) in the Hebrew University math
department building, at 10 am.

Speaker: Menachem Magidor (HUJI)

Title: Inner models constructed from generalized logics

Abstract: The constructible universe L is constructed in stages where
one uses first order definablity to define the successor stage. There
are interesting models that one gets if we replace first order logic
by generalized logic.It is well known if one uses full second order
logic one gets the model HOD. But what about logics which are between
first order and second order. We shall look at several cases and see
the interesting Set Theory that emerges form the study of these inner
models.

See you there!

An assistant professor position in mathematical logic, Charles University in Prague, Deadline: 31 October 2014

The Department of Algebra invites applications for a tenure-track position at the rank of assistant professor in the area of mathematical logic. The expected starting date is January 1, 2015 or soon afterwards and is negotiable.

Areas of special interest are:
(i) interactions of logic with computational complexity theory, or
(ii) model theory (any of its facets).
However, strong candidates in all areas of mathematical logic will be considered. Candidates are required to have a proven international research record corresponding to their career stage and a postdoctoral experience.

A successful candidate is expected to pursue an active research program, teach advanced and introductory classes in Czech and/or English and possibly supervise undergraduate and graduate students. Teaching in Czech is not required. (English is sufficient since the advanced classes may be taught in English even in standard undergraduate programs.)

The expected duration of the initial contract is three years. Such a position is renewable under a mutual agreement for another three years (and possibly for further three years, depending on the career stage). These new contracts depend on how successfully the assistant professor carries out research and teaching duties. Then, subject to a separate review process (called a habilitation), a promotion to the rank of associate professor is usual. This promotion is usually connected with a tenure. However, if the candidate’s career is already advanced with a strong research record, the initial period can be substantially reduced and you can progress to the promotion very fast.

Electronic applications accompanied by:

a curriculum vitae
a proof of PhD in a relevant field
a list of publications
a description of pedagogical experience

should be sent to Mrs. Eva Ramesova at ramesova@karlin.mff.cuni.cz.
The candidate should also arrange for two letters of recommendation to be sent directly to the same address. Informal inquiries are welcome and may be sent to Prof. Jan Krajicek at krajicek@karlin.mff.cuni.cz.
The application deadline is October 31, 2014.

Early applications are encouraged; applications may be processed as they are received.

We may invite the best candidates for an interview during October – mid November; after that the final round of selection will follow.

http://www.karlin.mff.cuni.cz/katedry/ka/ka.htm
http://www.mff.cuni.cz/to.en/fakulta/prace/

Giorgio Laguzzi: Roslanowski and Spinas dichotomies

Monday, July 14, 2014, 16.30
Seminar room 0.011, Mathematical Institute, University of Bonn

Speaker: Giorgio Laguzzi (Universität Hamburg)

Title: Roslanowski and Spinas dichotomies

Yair Hayut: Stationary reflection at successors of singulars

Forcing seminar (Tel Aviv University)
Yair Hayut will speak this Tuesday (8/7/14)
(9:10-11, Schreiber 209) his abstract :
Stationary reflection at successors of singulars
I will show how to get, starting with ω supercompact cardinals, a model in which every stationary set at some specific, predefined, successor of singular reflects. This is a simplification of results of Shelah and Magidor for the 80′s and 90′s. The reflection properties obtained this way are indestructible by closed enough forcing, so we can separate some combinatorical properties this way.  For this end, I define the approachability property and show its relations to preservation of stationary sets under closed forcing notions.
If time permits, I’ll show how to obtain Shelah’s model, in which every stationary set that can reflect reflects in the same way.