Postdoc position in Münster (Deadline October 2)

The Institute for Mathematical Logic and Foundations at the University of Münster announces a position as wissenschaftliche Mitarbeiterin/wissenschaftlicher Mitarbeiter in the project “Inner model theory and forcing” with Prof. Ralf Schindler beginning 01.12.2017 for three years with a possible extension. The application deadline is October 2, 2017.




On the Infinite

On the Infinite: An Interdisciplinary Symposium

Institute Henri Poincaré, October 18 – October 20, 2017 and Sorbonne October 21, 2017

Infinity: the break in the horizon, the “what cannot be counted”, boundless, bottomless, eternal, illimitable and absolute. The infinite encloses physical space; the infinite holds time within itself.

Already in the classical period, philosophers were undone by Zeno’s paradox, that an arrow shot from its bow will never reach its target because it must pass through every point between bow and target, and there are infinitely many such points. For cosmologists, the urgent question is: Is the universe finite or infinite? Will it last forever? And theologians saw in it an attribute of God, and were even prohibited to talk about it.

For the mathematician the infinite is the oil in the machine. For the mathematician who is a set theorist the infinite is a totality—completed, though in Aristotle’s sense, out of view; while at the same time the infinite is essentially open: open “above”, so numberless; but also open inwardly, in the way it copies itself internally over and over again, prints an image of itself into every one of its proper parts, and reprints, and reprints, and reprints, toward an endlessly fractured and ramified whole.

Critical conceptions of the infinite coming from outside of mathematics may coalesce around the concept of seriality. In The Infinite Line the art historian Briony Fer writes of the various serial strategies available to the artist; how “repetition, splintered into multiple registers, [is] no longer pitched against the aura of a single, unique artwork, so much as against its other selves.”

In this four-day interdisciplinary symposium we juxtapose lectures by set theorists and other mathematicians with those by art historians, architects, artists and philosophers, in an attempt to create a dialogue across cultures.

Some of the mathematical talks will be aimed at a general audience.

The symposium is accompanied by an exhibition of the work of the sculptor Fred Sandback.

Invited Speakers:

Yves André (mathematics, Paris VI)
Andrew Arana (philosophy, IHPST Paris)
Joan Bagaria (mathematics, Barcelona)
Emily Brady (philosophy, Edinburgh)
Maria Clara Cortés (art, Universidad Nacional de Colombia)
Briony Fer (art history, UCL)
Sebastian Gandon (philosophy, Clermont-Ferrand)
Wilfrid Hodges (mathematics, QML emeritus)
Hanna Johansson (art history, Helsinki)
Menachem Magidor (mathematics, Hebrew University)
Maryanthe Malliaris (mathematics, University of Chicago)
Philip Ording (mathematics, Sarah Lawrence College)
Juhani Pallasmaa (architecture, Helsinki)
Marja Sakari (art history, Kiasma, Helsinki)
SMITH (artist, Paris)
John Steel (mathematics, Berkeley)
Valdimir Tasic (mathematics, University of New Brunswick)
Jean-Philippe Uzan (CNRS, Institut d’Astrophysique de Paris)
Andres Villaveces (mathematics, Bogotá)
Philip Welch (mathematics, Bristol)
Hugh Woodin (mathematics and philosophy, Harvard)

Exhibition: Fred Sandback at the Institute Henri Poincaré.


Michael Harris, Columbia University, New York
Juliette Kennedy, University of Helsinki
Boban Velickovic, Paris Diderot University


Finnish Academy of Science and Letters
Institute Français de Finland
University of Helsinki
Institute Henri Poincaré
European Research Council
Magnus Ehrnrooth Foundation

Symposium on the Foundations of Mathematics 4 – Reverse Mathematics

9 – 11 October 2017, Munich Center for Mathematical Philosophy, LMU Munich

Reverse mathematics is concerned with examining exactly which axioms are necessary for various central mathematical theorems and results. The program is a relatively new one in the foundations of mathematics. Its basic goal is to assess the relative logical strengths of theorems from ordinary (non-set-theoretic) mathematics. To this end, for a given mathematical theorem T, one tries to find the minimal natural axiom system that is capable of proving T. In logical terms, finding the minimal axiom system equates to finding a collections of axioms such that each axiom follows from T (assuming a weak base system of axioms). In doing so, one shows that each axiom is necessary for T to hold. Because, by hypothesis, T follows from the axioms as well, the goal of reverse mathematics is to find axiom systems to which the theorems of ordinary mathematics are equivalent. It turns out that most theorems are equivalent to one of five subsystems of second order arithmetic.

The main objective of the conference is to explore the philosophical significance of reverse mathematics as a research program in the foundations of mathematics. The event will provide a forum for experts and early career researchers to exchange ideas and develop connections between philosophical and mathematical research in reverse mathematics. Specifically, the following research questions will be addressed:

1. How are philosophical debates informed by divisions between the relevant five subsystems of second order arithmetic, e.g., the debate between predicativism and impredicativism?

2. How should we understand the divisions between these five systems in terms of any natural distinctions they map on to?

3. How exhaustive are these five systems, especially in the sense of how they map onto natural divisions?

4. How does reverse mathematics relate to and inform our understanding of more traditional foundations of mathematics like ZFC, e.g., concerning the existence of large cardinals?

Confirmed Speakers:

Marianna Antonutti Marfori (Munich Center for Mathematical Philosophy, LMU Munich)
Walter Dean (University of Warwick)
Benedict Eastaugh (University of Bristol)
Marcia Groszek (Dartmouth College)
Takako Nemoto (Japan Advanced Institute of Science and Technology)
Stephen G. Simpson (Pennsylvania State University and Vanderbilt University)

Call for Abstracts:

We invite the submission of abstracts, suitable for a 40 minute talk, on topics related to any aspects of reverse mathematics. We encourage submissions from early-career researchers and PhD students. Please send an abstract of around 1000-1500 words by email to in PDF format. Abstracts should be prepared for blind review. The author’s name, paper title, institutional affiliation, and contact details should be included in the email.

Dates and Deadlines:

Submission deadline: 6 August 2017
Notification of acceptance: 15 August 2017
Registration deadline: 1 October, 2017
Conference: 9 – 11 October, 2017

For further details on the conference, please visit:


Carolin Antos-Kuby (University of Konstanz), Neil Barton (Kurt Gödel Research Center, Vienna), Lavinia Picollo (Munich Center for Mathematical Philosophy), Claudio Ternullo (Kurt Gödel Research Center, Vienna), John Wigglesworth (University of Vienna)

SotFoM4: Reverse Mathematics is generously supported by the Munich Center for Mathematical Philosophy, LMU Munich, and the Deutsche Forschungsgemeinschaft.

British Logic Colloquium 2017

The British Logic Colloquium will take place at the University of Sussex on
8-9 September 2017, with the BLC PhD day on 7 September.

This is the annual meeting of the British Logic Colloquium. The scope of
the event includes mathematical and philosophical logic as well as logic in
computer science and applications of logic.

SPONSORS. We are grateful for support from The London Mathematical Society


? Hazel Brickhill, University of Bristol, UK
? Oliver Kullmann, Swansea University, UK
? James Ladyman, University of Bristol, UK
? Sam Staton, Oxford University, UK
? Tamara von Glehn, Cambridge University, UK
? Katrin Tent, Universität Münster, Germany


? Martin Hyland, Cambridge
? Charlotte Kestner, Lancaster
? Ekaterina Komendantskaya, Heriot-Watt University
? Bernhard Reus, Sussex (chair)
? Monika Seisenberger, Swansea
? Philip Welch, Bristol


There will be a reduced conference fee for PhD students. Affordable
accommodation on campus will be available through the organisers as early
September is still tourist season in Brighton and hotels in the city centre
will be expensive. The campus is just a 9min train ride away from the city
centre. More info coming soon.


There will be a few slots available for contributed talks. If you would
like to present your recent work, either already published or work in
progress, please submit a single page abstract (A4 pdf) via EasyChair  ( by 20th July.

For more details please contact Bernhard Reus <>.

Workshop on Computability Theory and Foundations of Mathematics, Singapore

Workshop on Computability Theory and Foundations of Mathematics
(National University of Singapore, 8 – 12 September 2017)
Abstracts of talks should be submitted via email to
with subject line: CTFM2017 submission.
The length of abstract is limited to 2 pages including references.
The authors are recommended to prepare their abstracts in the
following IMS format:
IMPORTANT DATE. Submission deadline: September 1, 2017.
This workshop is the seventh in the Computability Theory and
Foundations of Mathematics (CTFM) series. CTFM aims to provide a forum
for computability theory and logical foundations of mathematics. The
topics include, but are not limited to, Computability / Recursion
Theory, Reverse Mathematics, Nonstandard Analysis, Proof Theory, Set
Theory, Philosophy of Mathematics, Constructive Mathematics,
Algorithmic Randomness and Computational Complexity.
CTFM began as a “Workshop on Proof Theory and Computability Theory”
and held its first meeting in Japan. Previous venues were Matsushima
(2008, 2009), Inawashiro (2010), Sendai (2011), Tokyo (2012). The
series assumed the name “Computability and Foundations of Mathematics”
at the 2013 meeting which was hosted in Tokyo. CTFM 2017 will be the
first time a meeting in the series is held outside Japan.
The previous meetings attracted not only researchers in Japan but also
many from around the world. In particular, since 2013, logicians from
Singapore have had frequent scientific exchanges with their Japanese
counterpart through the platform of the CTFM meetings.
The first day and the last day of the 2017 workshop will focus on
classical recursion theory, and computable structures as well as
reverse mathematics. The activities are held jointly with the program
Aspect of Computation. The other two days will focus on topics in set
theory and the foundations of mathematics.
Invited Speakers
Joerg Brendle (Kobe University, Japan)
Satoru Kuroda (Gunma Prefectural Women”s University, Japan)
Ludovic Patey (The University of California, Berkeley, USA)
Toshimichi Usuba (Waseda University, Japan)
Thomas Zeugmann (Hokkaido University, Japan)
Hao Zhaokuan (Fudan University, China)
Program Committee:
Dilip Raghavan (National University of Singapore)
Stephen Simpson (Pennsylvania State University)
Frank Stephan (National University of Singapore)
Kazuyuki Tanaka (Tohoku University) (Chair)
Yue Yang (National University of Singapore)
Keita Yokoyama (Japan Advanced Institute of Science and Technology)
Organizing Committee:
Chi Tat Chong (National University of Singapore)
Kazuyuki Tanaka (Tohoku University)
Guohua Wu (Nanyang Technological University)
Yue Yang (National University of Singapore)
Keita Yokoyama (Japan Advanced Institute of Science and Technology)

Third Hausdorff Medal 2017

Ladies and gentlemen, dear friends and colleagues!

It is my honor and pleasure to announce the winner of the third Hausdorff medal of the European Set Theory Society. The Hausdorff medal is awarded biennially (i.e. once every second year) for the most influential work in set theory published in the five years preceding the awarding of the medal. The prize committee, that consists of the members of the Board of Trustees of the Society, decided that the third Hausdorff medal is awarded to Maryanthe Malliaris and Saharon Shelah for their work outlined in the paper:

General topology meets model theory, on p and t. Proc. Natl. Acad. Sci. USA 110 (2013), no. 33, 13300-13305,

and then expounded in the detailed, 60 page long version:

Cofinality spectrum theorems in model theory, set theory, and general topology. J. Amer. Math. Soc. 29 (2016), no. 1, 237-297.


Malliaris and Shelah solved two long-standing and fundamental problems:

First, they solved a more than 50 year old set theoretic problem, going back to Rothberger, by showing that the well-known and important cardinal characteristics p and t of the continuum are actually equal.

Secondly, they solved a 40 year old problem in model theory by showing that the maximality in Keislers order is not characterized by the strict order property, but that a weak order property called SOP2 suffices.

Both results follow from a brilliant analysis of definability in ultraproducts of finite linear orders. This analysis is also unique in proving that there are theories more complex than the stable, i.e. minimal theories but less complex than the maximal class in Keisler’s order.

To conclude, this important work of Malliaris and Shelah opens the door for significant and fruitful new interactions between set theory and model theory.


Saharon Shelah, Maryanthe Malliaris, István Juhász, Jouko Väänänen – photo by Joan Bagaria


István Juhász, Saharon Shelah, Maryanthe Malliaris, Jouko Väänänen – photo by Joan Bagaria

Upcoming set theory meetings

May 29: Borel Reducibility of Equivalence Relations, Lausanne
June 20-25: Set Theoretic Pluralism – Symposium 2
June 26-30: Seventeenth Latin American Symposium on Mathematical Logic, Puebla, Mexico
June 27-30: 32nd Summer Conference on Topology and its Applications, Dayton, US
July 3-7: 6th European Set Theory Conference, Budapest
July 10-14: 10th Young Set Theory Workshop, Edinburgh
July 10-14: The 15th Asian Logic Conference, Korea
July 14-25: Graduate summer school: Classification problems in ergodic theory, Irvine
July 31-August 4: Applications of model theory to operator algebras, Houston
August 2-4: A conference on the occasion of Jensen’s 80th birthday, Münster
August 7-11: Nordic Logic Summer School 2017, Stockholm
August 14-18: Boolean Algebras, Lattices, Universal Algebra, Set Theory, Topology (BLAST), Nashville
August 14-20: Logic Colloquium 2017, Stockholm
August 20-September 1: Frontiers of Selection Principles, Warsaw
September 3-9: Set Theoretic Methods in Topology and Analysis, Bedlewo, Poland
September 6-8: Descriptive set theory in Torino
September 7-12: Set theoretic & Topological methods in Model Theory, Tezpur, India
September 10-12: Homogeneous structures, permutation groups, and connections to set theory, in honour of the 70th birthday of John Truss, Leeds
September 15-17: Simon Thomas: the first 60 years, Rutgers
October 9-13: The 14th international Luminy workshop on set theory, CIRM, Marseille
November 6-9: RIMS set theory meeting, Kyoto
November 13-17: Second Pan Pacific International Conference on Topology and its Applications, Busan, South Korea