Archives of: Samuel Coskey

Thematic Semester on Descriptive Set Theory and Polish groups, More info

Thematic Semester on Descriptive Set Theory and Polish groups
Bernoulli Center, Lausanne, Switzerland.
January – June, 2018.

During the period January 1st – June 30th, 2018, there will be a thematic semester on Descriptive Set Theory and Polish Groups held at the Bernoulli Center in Lausanne, Switzerland.

The semester is organised around five week long activities, including three conferences and two workshops, along with three Bernoulli Lectures held in connection with these events.
Conference: Borel combinatorics and ergodic theory (organised by C. Conley and D. Gaboriau), February 5-9.
Bernoulli Lecture: Stephen Jackson (Univ. North Texas), February 8.
Conference: Structure and dynamics of Polish groups (organised by A. Thom and T. Tsankov), March 19-23.
Workshop: Large scale geometry of Polish groups (organised by J. Moore and C. Rosendal), March 26-29.
Bernoulli Lecture: Mikhail Gromov (IHES) – What is Probability? March 27.
Workshop: Ideals and exceptional sets in Polish spaces (organised by M. Elekes and S. Solecki), June 4-8.
Conference: Descriptive set theory (organised by B. Miller, A. Kechris and S. Todorcevic), June 18-22.
Bernoulli Lecture: Slawomir Solecki (Cornell) – Projective Fraisse limits, approaching topology through logic. June 21.
In addition to these semester activities, the 11th Young Set Theory Workshop will be held at the Bernoulli Center during the week of June 25-29.

Detailed information about the semester and these event is available at the following link

The Bernoulli Center has large capacity and everyone is invited to attend the events of the semester. Registration for the individual events can be done through the above link by clicking at the conference/workshop in the right column.

Funding for US based visitors is secured through an NSF grant, while limited funding for other participants is also available. Requests for funding should be made during online registration.

Please note that registration and funding requests for the events in March should be made before mid-December.

Symposium of the Set Theoretic Pluralism network, Bristol, June 20-25

The second and final symposium of the Set Theoretic Pluralism (STP) network will take place at the University of Bristol on June 20-25, 2017. We would like to invite researchers from all relevant disciplines to attend the symposium, including set theory, philosophy of mathematics, metaphysics, philosophy of language, and epistemology.

The STP network draws together experts in mathematics and philosophy to grapple with the increasingly popular idea that mathematical reality may be best understood as fractured and indeterminate. Participants will include Sy David Friedman (Vienna), Peter Koellner (Harvard), Hugh Woodin (Harvard), Sean Walsh (UC Irvine), Toby Meadows (Queensland), Philip Welch (Bristol), Giorgio Venturi (Campinas), Carolin Antos (Vienna), Neil Barton (Vienna), Zeynep Soysal (Harvard), and Benedict Eastaugh (Bristol).

Registration for the symposium is now open (participation is free, but registration is required). The registration deadline is Monday 5 June, 2017.

To register, please email and include the following information:

* Name and affiliation.

* Whether you would like to attend the conference dinner, scheduled for Thursday 22 June, 2017. Places are limited and will be allocated on a first-come, first-served basis.

* Any dietary restrictions or preferences.

* Which days you plan to attend the symposium, if you are not attending the entire event.

Further details of the symposium, including the programme and details of the location, will be published on the symposium website:

The STP network is funded by a Leverhulme International Network grant and is hosted at the University of Bristol. The STP network partners include the University of Aberdeen, Harvard University, the University of Bristol, the University of Vienna, the University of Helsinki, and the University of California, Irvine. For more details of the network’s context and aims, please refer to the network website:

We look forward to seeing you here!

Toby Meadows, Philip Welch, and Benedict Eastaugh

Applications of model theory to operator algebras, Houston, July 31 – August 4

Dear Colleagues,

This is an announcement for an NSF-funded conference on “Applications
of Model Theory to Operator Algebras” to be held at the University of
Houston from July 31 — August 4, 2017. This conference will feature a
lecture series by our main speaker, Ilijas Farah, as well as several
plenary research talks by various experts in Operator Algebras and
Model Theory.

The purpose of this conference is two-fold: First, to serve as a
“master class” for non-experts and young researchers to learn about
fundamental concepts presented by Professor Ilijas Farah, a leading
expert and renowned expositor of these topics; and second, to inform
and update experts in other areas of operator algebras about the
latest advances and achievements of the subject. More information on
these talks, and the topics covered, can be found on the conference

We hope you will be able to attend.


The Organizers
Mehrdad Kalantar (University of Houston)
Mark Tomforde (University of Houston)
Ping Wong Ng (University of Louisiana at Lafayette)
Leonel Robert (University of Louisiana at Lafayette)

Simon Thomas: the first 60 years, Rutgers, September 15-17, 2017

The conference Simon Thomas: the first 60 years will take place this September 15–17 at Rutgers University, New Brunswick, New Jersey.

List of speakers

  • Clinton Conley
  • Ilijas Farah
  • Matt Foreman
  • Alekos Kechris
  • Justin Moore
  • Andrew Marks
  • Itay Neeman
  • Anush Tserunyan
  • Robin Tucker-Drob
  • Saharon Shelah
  • Hugh Woodin (canceled)

Grigor Sargsyan

    1. Schedule.

      Each talk is 50 minutes with 10 minutes devoted to questions and extras.

      Day 1. Friday September 15.

      All Friday talks will take place in Hill 705.

      9:00am–10:00am Saharon Shelah (Jerusalem, Rutgers)
      Title: ZFC constructing somewhat free Abelian group with prescribed endomorphism ring

      10:30am-11:30am Robin Tucker-Drob (Texas A&M)
      Title: Invariant means and lattices in totally disconnected locally compact groups

      2:30pm–3:30pm Clinton Conley (CMU)
      Title: Borel, mu-measurable, and Baire measurable matchings.

      4:00pm–5:00pm Matthew Foreman, cross listed as the colloquium talk. (UCI)
      Title: Classifying diffeomorphisms of surfaces
      Abstract: In 1932, von Neumann proposed classifying the statistical behavior of diffeomorphisms of manifolds. In modern language this means classifying diffeomorphisms that preserve a smooth volume element up to measure theoretic isomorphism. Despite important progress using entropy and spectral invariants, the general problem remained open. This talk proves that a complete classification is impossible in a rigorous sense—even on compact surfaces. The proof of the theorem involves producing new examples of diffeomorphisms with strong structural properties such as high distal rank.

      5:10pm–6:00pm (Special Talk) Francis Urquhart (Rutgers)
      Title: The classification problem of FU groups is positively complex.

      Day 2. Saturday September 16.

      All Saturday talks will take place at Rutgers Conference Center.

      9:00am–10am Itay Neeman (UCLA)
      Title: Embedding theorem and regularity properties under $AD^+$
      Abstract: We present an absoluteness theorem under $AD^+$, showing approximately that proper forcing extensions of sufficiently elementary countable submodels can be embedded back into the universe. We use this embedding theorem to prove, under $AD^+$, that all sets of reals have the Ramsey property, and in fact are $H$-Ramsey for every happy family $H$. This in particular implies that there are no infinite MAD families under $AD^+$. We also use the embedding theorem to prove, again under $AD^+$, that for any equivalence relation $E$ whose equivalence classes belong to a pointclass $\Gamma$ closed under Borel substitutions (respectively to $\Gamma\cap\check{\Gamma}$), and any nice enough $\sigma$-ideal $I$ on $\omega^\omega$, there are $I$-positive sets $C$ so that $E\restriction C$ belongs to $\Gamma$ (respectively $\Gamma\cap\check{\Gamma}$). This is joint work with Zach Norwood. The embedding theorem extends a result of Neeman-Zapletal. The application to mad families extends a result of Tornquist restoring methods of Mathias. The application to equivalence relations extends results of Chan-Magidor.

      10:30am–11:30am Anush Tserunyan (Urbana)
      Title: Hyperfinite ergodic subgraphs
      Abstract: Using the work of Hutchcroft and Nachmias on indistinguishability of the Wired Uniform Spanning Forest, R. Tucker-Drob proved a powerful theorem last year: any probability measure preserving (p.m.p.) locally countable ergodic Borel graph admits an ergodic hyperfinite subgraph. By completely different and purely descriptive set theoretic methods, we prove this theorem without the p.m.p. requirement, thus obtaining the following generalization: any locally countable ergodic Borel graph on a standard probability space admits an ergodic hyperfinite subgraph. In this talk, we will discuss the main result and one or two new gadgets involved in the proof.

      2:30pm–3:30pm Ilijas Farah (York)
      Title: Approximately matricial C*-algebras Abstract: A unital C*-algebra A is AM (approximately matricial) if it is an inductive limit of a directed system of full matrix C*-algebras. Separable AM algebras were classified by Glimm (the equivalence relation is smooth) and they form the simplest nontrivial class of simple (no pun intended) C*-algebras, also known as the UHF (uniformly hyperfinite) C*-algebras. Some years ago it was proved by Katsura and myself that not every nonseparable AM algebra is UHF. I’ll talk about more recent interesting examples of AM algebras and the role of set theory in constructing them.

      4:00pm-5:00pm Justin Moore (Cornell)
      Title: Subgroups of Thompson’s group F

      Day 3. Sunday September 17.

      All Sunday talks will take place at Rutgers Conference Center.

      9:30am–10:30am Aleksander Kechris (Caltech)
      Title: Borel equivalence relations, cardinal algebras and structurability.
      Abstract: The theory of Borel equivalence relations has been a very active area of research in descriptive set theory during the last 25 years. In this talk, I will discuss how Tarski’s concept of cardinal algebras, going back to the 1940’s, appears naturally in this theory and show how Tarski’s theory can be used to discover new laws concerning the structure of Borel equivalence relations, which, rather surprisingly, have not been realized before. In addition, I will discuss the concept of structurability for equivalence relations and explain some of its implications concerning the algebraic structure of the reducibility order among such equivalence relations. (This is joint work with H. Macdonald and R. Chen.)

      11am–12pm Andrew Marks (UCLA)
      Title: Martin’s measure and countable Borel equivalence relations
      Abstract: Thomas has shown that Martin’s conjecture on Turing invariant functions would have a wealth of consequences for the structure of countable Borel equivalence relations. Many of these consequences derive from the strong ergodicity properties that the conjecture implies for Martin measure. We discuss some results related to Martin measure and countable Borel equivalence relations. This is joint work with Adam Day, and also Clinton Conley, Steve Jackson, Brandon Seward and Robin Tucker-Drob.

MAMLS at VCU, April 1-2, 2017

MAMLS at VCU will be a gathering of set theorists working on large cardinals, inner models, forcing and relative consistency results, sponsored by the NSF and the Department of Mathematics and Applied Mathematics at Virginia Commonwealth University. While graduate students, young researchers, female mathematicians and members of underrepresented groups are particularly encouraged to apply for travel support, it should be stressed that any participants without their own sources of funding are eligible to apply. Requests will be handled on a case-by-case basis within the limits of the budget. To apply for travel support, contact

The meeting begins at 8:30am on April 1 and ends at 12pm on April 2. See the web site for more information and updates:


Omer Ben-Neria University of California at Los Angeles
James Cummings Carnegie Mellon University
Monroe Eskew Virginia Commonwealth University
Victoria Gitman City University of New York
Joel David Hamkins City University of New York
John Krueger University of North Texas
Dima Sinapova University of Illinois at Chicago
Hugh Woodin Harvard University

Thematic semester on Descriptive Set Theory and Polish Groups

This is an announcement of the forthcoming thematic semester on Descriptive Set Theory and Polish Groups that will take place at the Bernoulli Center in Lausanne, Switzerland, from January 1st to June 30th, 2018.

The focus of the semester will be on Descriptive Set Theory and Polish Groups along with applications in other branches of mathematics. While there will be continuous activity at the center throughout the semester, three conferences and two additional workshops will provide the main events. The themes of these will be

Borel combinatorics and ergodic theory
Structure and dynamics of Polish groups
Descriptive set theory
Ideals and exceptional sets in Polish spaces
Large scale geometry of Polish groups

2017 North American ASL Meeting: March 20-23, 2017

Conference web site

Plenary speakers
M. Aschenbrenner (UCLA)
C. Conley (Carnegie Mellon University)
I. Kalimullin (Kazan Federal Univeristy)
P. Koellner (Harvard University)
A. Medvedev (City College of New York)
A. Rinot (Bar-Ilan University)
M. Seisenberger (Swansea University)

V. Harizanov (George Washington University)

Special Sessions
Continuous model theory (Bradd Hart and Ward Henson)
Computable structure theory (Denis Hirschfeldt and Russell Miller)
Applications of set theory to topology and analysis (Michael Hrusak and Marion Scheepers)
Complexity theory and automated proofs (Sam Buss and Vijay Ganesh)
Philosophy Session (Kenneth Easwaran and Catarina Dutilh Novaes)

Program Committee
Liljana Babinkostova, Boise State University
Gregory Cherlin, Rutgers University
Barbara Csima, University of Waterloo
Antonina Kolokolova, Memorial University of Newfoundland
Justin Moore (chair), Cornell University

Local organizers
Liljana Babinkostova
Andrew Cortens
Samuel Coskey
Stephen Crowley
Randall Holmes
Alex Jackson
Marion Scheepers

BEST 2016 slides

The 23rd BEST conference was held June 15–16 in San Diego, CA.

Shehzad Ahmed – Jonsson cardinals and pcf theory
Liljana Babinkostova – A weakening of the closure operator
Kyle Beserra – On the conjugacy problem for automorphisms of countable regular trees
Erin Carmody – Killing them softly
William Chan – Every analytic equivalence relation with all Borel classes is Borel somewhere
John Clemens – Relative primeness of equivalence relations
Paul Corazza – The axiom of infinity, quantum field theory, and large cardinals
Cody Dance – Indiscernibles for $L[T_2,x]$
Natasha Dobrinen – Ramsey spaces coding universal triangle-free graphs and applications to Ramsey degrees
Paul Ellis – A Borel amalgamation property
Monroe Eskew – Rigid ideals
Daniel Hathaway – Disjoint Borel functions
Jared Holshouser – Partition properties for non-ordinal sets under the axiom of determinacy
Paul McKenney – Automorphisms of $\mathcal P(\lambda)/\mathcal I_\kappa
Kaethe Minden – Subcomplete forcing and trees
Daniel Soukup – Orientations of graphs with uncountable chromatic number
Simon Thomas – The isomorphism and bi-embeddability relations for finitely generated groups
Douglas Ulrich – A new notion of cardinality for countable first order theories
Kameryn Williams – Minimal models of Kelley-Morse set theory
Martin Zeman – Master conditions from huge embeddings

Large Cardinals and Strong Logics: September 5 through December 16

Dear colleague,

We would like to inform you about the forthcoming CRM Intensive Research Program on Large Cardinals and Strong Logics, to be held from September 5 to December 16, 2016.

The National Science Foundation and the Association for Symbolic Logic offer grants to participate in the program and its scientific events. You can check the program’s web page for further information at


Many natural mathematical concepts cannot be expressed in first-order logic but need stronger logics. Among such concepts are the freeness of a group, separability of a space, completeness of an order, etc. By a strong logic we mean model-theoretically defined extensions of first-order logic, such as first-order logic with generalized quantifiers, infinitary logics, second-order logic, as well as higher-order logics. The study of strong logics runs immediately into questions that depend essentially on set-theoretical assumptions beyond the standard ZFC axioms, such as infinitary combinatorial principles and the existence of large cardinals. It is therefore crucial to be able to pinpoint the position of a given strong logic in the set-theoretical definability hierarchy, thus helping us understand better the set-theoretical nature of the logic, and therefore of the mathematical notions it can express.


This program will bring to the CRM a diverse group of international high-level researchers working in strong logics, large cardinals, the foundations of set theory, and the applications of set-theoretical methods in other areas of mathematics, such as algebra, set-theoretical topology, category theory, algebraic topology, homotopy theory, C*-algebras, measure theory, etc. In all these areas there are not only direct set-theoretical applications but also new results and methods, which are amenable to the expressive power of strong logics.

During the Research Program the following activities will be held:

Advanced Course on Large Cardinals and Strong Logics, from September 19 to 23, 2016.
Deadline for registration: August 1st, 2016. More information on registration and grants available at

Workshop 1: Set-theoretical aspects of the model theory of strong logics, from September 26 to 30, 2016.
Deadline for registration: August 1st, 2016. More information on registration and grants available at

Young researcher’s Seminar week, from November 7 to 11, 2016.
You can participate by presenting your work before October 31, 2016.
More information on how to participate at’s-Seminar-week.aspx

Workshop 2: Applications of strong logics in other areas of mathematics, from November 14 to 18, 2016.
Deadline for registration: November 6, 2016. More information on registration and grants available at Note: This workshop will take place in Barcelona, in the old University of Barcelona building (not in Bellaterra).

Please, feel free to distribute this information among your colleagues.

We hope you find this information useful and look forward to hosting you at the CRM.
Joan Bagaria (Universitat de Barcelona), Menachem Magidor (Einstein Institute of Mathematics of The Hebrew University of Jerusalem), and Jouko Väänänen (University of Helsinki).
Program’s Scientific Organizers

23rd Boise Extravaganza in Set Theory, June 15-16, 2016

Conference Website:
DATE: June 15 – 16, 2016
WHERE: University of San Diego

The 23-rd annual meeting of BEST will be hosted at the University of San Diego as a symposium of the 97th annual meeting of the American Association for the Advancement of Science – Pacific Division (AAAS-PD). Contributed and invited talks at BEST will be held on Wednesday and Thursday.
In addition to the invited speakers, the conference program has several speaking slots for shorter talks. We strongly encourage students, post docs and pre-tenure tenure track faculty to present at BEST. NSF supported funding to assist a limited number of student speakers, post-doc speakers and pre-tenure tenure track faculty speakers is available. For details on applying to the BEST program committee for these, please visit the conference website at the URL provided above. In addition, the AAAS-PD provides up to $150 in travel funding for students. Please see the BEST conference website for more details on these also. There are a number of deadlines associated with applications for a travel grant.

Currently confirmed plenary speakers for BEST 2015 are:

Dr. Erin Carmody, Nebraska Wesleyan University
Dr. Natasha Dobrinen, University of Denver
Dr. Simon Thomas, Rutgers University
Dr. Martin Zeman, University of California – Irvine

Special features of BEST 2016 include:

In addition to the BEST symposium there are several other symposia and workshops of interest offered at the AAAS-PD annual meeting. On Thursday, June 16, the AAAS-PD hosts a banquet at which awards of excellence are given to student speakers selected by a panel of judges.

Student, post-doc and pre-tenure tenure track speakers are strongly encouraged to apply to BEST for an NSF-funded travel award. The travel expenses (airfare and lodging) of awarded speakers will be reimbursed up to the maximum amount of the award, and registration fees of awardees will be reimbursed.

BEST seeks to promote student participation in the conference via short (20 minute) presentations. To this end there are eight (8) NSF funded BEST travel awards available for students. To apply for one of these awards, please follow the instructions given at the BEST website.

In addition to the BEST travel awards, up to 20 travel awards of up to $150 each are also available from the AAAS-PD to help students (including students participating in BEST) defray travel expenses to participate in the AAAS-PD annual meeting. Winners of these AAAS-PD travel awards will be announced at the AAAS-PD student award banquet. Student participants will be guests at this banquet.

BEST also seeks to be a forum for early career set theoretic scholars. In particular there are NSF funded BEST travel awards available for post-docs, and for pre-tenure tenure track faculty. To apply for one of these awards, please follow the instructions given at the BEST website.\


The BEST schedule will also have a number of slots for 25 minute contributed talks. Anyone wishing to speak at BEST 2016 should submit an abstract as soon as possible (preferably prior to April 05) at the abstract submission site. It is strongly recommended to also contact one of the organizers as soon as possible to indicate interest/intention in presenting a talk at BEST 2016.

Important deadlines:

DEADLINE 1: REGISTRATION: Please consult for registration costs and deadlines. Registration fees depend on date of registration. We kindly request that Ph.D. mathematicians planning to participate in BEST 2016 consider acting as judges for the student presentations. The registration form has a place where willingness to act\’a0 as a judge can be indicated.

There are also a number of excursions available that can be indicated on the registration form. Also consider attending the awards banquet in support of our student speakers – meal choices are available on the registration form.

DEADLINE 2: ABSTRACTS: Atlas Conferences, Inc. is providing abstract services for BEST 2016. Abstracts submitted by April 5 will appear in the proceedings of the annual conference of the AAAS-PD. The url for the abstract submission is available at the BEST 2016 website.

DEADLINE 3: TRAVEL GRANTS: Presenting students, post-docs or pre-tenure tenure track faculty, please complete the application process to BEST by May 15. See the BEST 2016 website for details. Students, the deadline for the AAAS-PD student travel grants is May 1, 5:00 p.m. Pacific time.

Organized by Liljana Babinkostova, Sam Coskey and Marion Scheepers.

For any questions, please contact an organizer or e-mail