Damjan Kalajdzievski: How to show Con(ZFC + omega_1=u<a) from Con(ZFC)

Place: Fields Institute (Room 210)

Date: February 8 , 2019 (13:30-15:00)

Speaker: Damjan Kalajdzievski

Title: How to show Con(ZFC + omega_1=u<a) from Con(ZFC)

Abstract: I will outline how to prove the result in the title by joint work with Osvaldo Guzman

https://settheory.mathtalks.org/damjan-kalajdzievski-how-to-show-conzfc-omega_1ua-from-conzfc/

#DamjanKalajdzievski

Berkeley conference on inner model theory, July 08–19, 2019

Berkeley conference on

inner model theory

July 08--19, 2019

Organizers: Ralf Schindler (Münster) and John Steel (Berkeley).

This conference will be a sequel to the 1st Conference on the core model induction and hod mice that was held in Münster (FRG), July 19 -- August 06, 2010, to the 2nd Conference on the core model indu

https://settheory.mathtalks.org/berkeley-conference-on-inner-model-theory-july-08-19-2019/

Logic Fest in the Windy City, Chicago, May 30 – June 2, 2019

The conference will take place at the University of Illinois at Chicago on May 30 - June 2. We will cover topics in set theory, descriptive set theory, model theory, and various applications. The workshop is aimed at graduate students and

https://settheory.mathtalks.org/logicfest2019/

#AntonBernshteyn #ArtemChernikov #FilippoCalderoni #JohnKrueger #MaryantheMalliaris #NatashaDobrinen #SherwoodHachtman #SpencerUnger #WillBoney

Hossein Lamei Ramandi: $\Sigma^2_2$-absoluteness

Place: Fields Institute (Room 210)

Date: January 25 , 2018 (13:30-15:00)

Speaker: Hossein Lamei Ramandi

Title: $\Sigma^2_2$-absoluteness

Abstract: We will show there is a $\Sigma^2_2$ sentence $\Phi$ such that both $\Phi$ and $\neg \Phi$ are consistent with $\diamondsuit$. This answers a question due to Woodin.

https://settheory.mathtalks.org/hossein-lamei-ramandi-sigma2_2-absoluteness/

#HosseinLameiRamandi

Benjamin Vejnar – Complexity of the homeomorphism relation between compact spaces

Talk held by Benjamin Vejnar (Charles University, Prague, Czech Republic) at the KGRC seminar on 2019-01-24. Abstract: We study the complexity of the homeomorphism relation of compact metrizable spaces when restricted to some subclasses such as continua, regular continua or regular compacta. [...]

https://settheory.mathtalks.org/benjamin-vejnar-complexity-of-the-homeomorphism-relation-between-compact-spaces/

Marcin Sabok: Measurable Hall’s theorem for actions of Z^n

Place: Fields Institute (Room 210) Date: January 18, 2018 (13:30-15:00) Speaker: Marcin Sabok Title: Measurable Hall's theorem for actions of Z^n Abstract: In the 1920's Tarski asked if it is possible to divide the unit square into finitely many pieces, rearrange them by translations and get a disc of area 1. It turns out that this is[...]

https://settheory.mathtalks.org/marcin-sabok-measurable-halls-theorem-for-actions-of-zn/

Moritz Müller – Forcing against bounded arithmetic

Talk held by Moritz Müller (Universitat Politècnica de Catalunya, Barcelona, Spain) at the KGRC seminar on 2019-01-17. Abstract: We study the following problem. Given a nonstandard model of arithmetic we want to expand it by a binary relation that does something prohibitive, e.g. violates the pigeonhole principle in the sense that it is the graph…[...]

https://settheory.mathtalks.org/moritz-muller-forcing-against-bounded-arithmetic/

Menachem Magidor: Omitting types in the logic of metric structures

HUJI Logic Seminar 16/Jan/2019, 11-13, Ross 63. Speaker: Menachem Magidor Title: Omitting types in the logic of metric structures Abstract. (joint work with I. Farah) The logic of metric structures was introduced by Ben Yaacov, Berenstein , Henson and Usvyatsov. It is a version of continuous logic which allows fruitful mode[...]

https://settheory.mathtalks.org/menachem-magidor-omitting-types-in-the-logic-of-metric-structures/

Natasha Dobrinen – Mini-course on Infinitary Ramsey theory

Time and Place: Tuesday, January 8 and Wednesday, January 9 at 10:30am in the KGRC lecture room (both parts) at the KGRC. Part I. Topological Ramsey spaces and applications to ultrafilters Part II. Ramsey theory on trees and applications to big Ramsey degrees The Infinite Ramsey Theorem states that given $n,r\ge 1$ and a color[...]

https://settheory.mathtalks.org/natasha-dobrinen-mini-course-on-infinitary-ramsey-theory/

Natasha Dobrinen – Ramsey Theory of the Henson graphs

Abstract: A central question in the theory of ultrahomogeneous relational structures asks, How close of an analogue to the Infinite Ramsey Theorem does it carry? An infinite structure S is ultrahomogeneous if any isomorphism between two finitely generated substructures of S can be extended to an automorphism of S. We say that S has finite [...]

https://settheory.mathtalks.org/natasha-dobrinen-ramsey-theory-of-the-henson-graphs/

Miguel Moreno: An introduction to generalized descriptive set theory, part 2

BIU Infinite Combinatorics Seminar Date : 31/12/2018 - 13:00 - 15:00 Speaker: Miguel Moreno (BIU) Title : An introduction to generalized descriptive set theory, part 2 Abstract. After introducing the notions of $\kappa$-Borel class, $\kappa$-$\Delta_1^1$ class, $\kappa$-Borel^* class in the previous talk,[...]

https://settheory.mathtalks.org/miguel-moreno-an-introduction-to-generalized-descriptive-set-theory-part-2/

Ur Yaar: The Modal Logic of Forcing

HUJI Set Theory Seminar On Wednesday, December 26, Ur Yaar will talk about the modal logic of forcing. Title: The Modal Logic of Forcing Abstract: Modal logic is used to study various modalities, i.e. various ways in which statements can be true, the most notable of which are the modalities of necessity and possibility. In set-theory,…[...]

https://settheory.mathtalks.org/ur-yaar-the-modal-logic-of-forcing/

Matt Foreman: Games on weakly compact cardinals

TAU Forcing Seminar Tuesday, 25/12/18 Speaker: Matt Foreman Title: Games on weakly compact cardinals Abstract: Attached.[...]

https://settheory.mathtalks.org/matt-foreman-games-on-weakly-compact-cardinals/

Assaf Rinot: Hindman’s theorem and uncountable Abelian groups

Colloquium, Hebrew University of Jerusalem Thu, 20/12/2018 - 14:30 to 15:30 Location: Manchester Building (Hall 2), Hebrew University Jerusalem Speaker: Assaf Rinot Title: Hindman’s theorem and uncountable Abelian groups Abstract. In the early 1970’s, Hindman proved a beautiful theorem in additive Ramsey theory asserting that [...]

https://settheory.mathtalks.org/assaf-rinot-hindmans-theorem-and-uncountable-abelian-groups-2/

Daniel T. Soukup – New aspects of ladder system uniformization II

Talk held by Daniel Soukup (KGRC) at the KGRC seminar on 2018-12-13. Abstract: We continue the previous lecture and present proofs for some of the new results. We show that $\diamondsuit$ implies that for any Aronszajn-tree $T$, there is a ladder system with a 2-colouring with no $T$-uniformization. However, if $\diamondsuit^[...]

https://settheory.mathtalks.org/daniel-t-soukup-new-aspects-of-ladder-system-uniformization-ii/

Asaf Karagila: On countable unions of countable sets

BIU seminar in Set Theory December 17, 2018 Speaker: Asaf Karagila (UEA) Title: On countable unions of countable sets Abstract. How big can countable unions of countable sets be? Assuming the axiom of choice, countable. Not assuming the axiom of choice, it is not hard to arrange situation where there are many incomparable cardinals which…[...]

https://settheory.mathtalks.org/asaf-karagila-on-countable-unions-of-countable-sets/

Ilijas Farah: On the model theory of C*-algebras

HUJI Logic Seminar 12/December/18, 11 am, in Ross 63. Speaker: Ilijas Farah Title: On the model theory of C*-algebras Abstract. Ultrapowers and reduced products play a central role in the Elliott classification program for separable (nuclear, etc.) C*-algebras. Although an ultrapower of a separable C*-algebra A is quite different from the reduced product $\e[...]

https://settheory.mathtalks.org/ilijas-farah-on-the-model-theory-of-c-algebras/

Clovis Hamel: Stability and Definability in Continuous Logics, Cp-theory and the Tsirelson space.

Place: Fields Institute Library Date: Decembver 7, 2018 (13:30-15:00) Speaker: Clovis Hamel Title: Stability and Definability in Continuous Logics, Cp-theory and the Tsirelson space. Abstract: An old question in Functional Analysis inquired whether there is a Ba[...]

https://settheory.mathtalks.org/clovis-hamel-stability-and-definability-in-continuous-logics-cp-theory-and-the-tsirelson-space/

Stevo Todorcevic – Ramsey degrees of topological spaces

Talk held by Stevo Todorcevic (University of Toronto, Canada) at the KGRC seminar on 2018-12-04. Abstract: This will be an overview of structural Ramsey theory when the objects are topological spaces. Open problems and directions for further research in this area will also be examined.[...]

https://settheory.mathtalks.org/stevo-todorcevic-ramsey-degrees-of-topological-spaces/

James Cummings: Regular cardinals and compactness

Mathematical logic seminar - Dec 4 2018 Time: 3:30pm - 4:30 pm Room: Wean Hall 8220 Speaker: James Cummings Department of Mathematical Sciences CMU Title: Regular cardinals and compactness Abstract: This talk is a sequel of sorts to last week's talk on singular compactness, but is completely independent of it. I will [...]

https://settheory.mathtalks.org/james-cummings-regular-cardinals-and-compactness/

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Joined Apr 2018