© Picture taken by Stephen Givant, Berkeley, June 1971

Set theory conference

A conference on the occasion of Ronald B. Jensen's 80th birthday

Institut für Mathematische Logik und Grundlagenforschung, WWU Münster

Aug 02--Aug 04, 2017

Organizers: Menachem Magidor (Jerusalem), Ralf Schindler (Münster), John Steel (Berkeley), W. Hugh Woodin (Harvard)

List of speakers:

We acknowledge generous support by the SFB 878 Groups, Geometry, and Actions. We also acknowledge support from the German logic society, DVMLG.

Location: Lecture hall M6, Einsteinstrasse 62, Dept Math and CS, University of Münster.


Wed, Aug 02 Thu, Aug 03Fri, Aug 04
9:30--10:30 Gunter FuchsJohn Steel
11:00--12:00 Menachem Magidor Adrian MathiasItay Neeman
14:30--15:30 Moti Gitik Martin ZemanW. Hugh Woodin
16:00--17:00 Bill Mitchell Grigor Sargsyan
18:30--∞ Conference dinner

Talks and abstracts:

  1. Gunter Fuchs: Subcomplete forcing and its forcing principles

    Subcomplete forcing was introduced by Ronald Jensen. It is a class of forcings that don't add reals, are stationary set preserving, but may change cofinalities of regular cardinals to be countable. Jensen showed that Martin's axiom for subcomplete forcing is consistent, assuming the consistency of a supercompact cardinal, and that it is consistent with CH. This makes forcing principles for this class of forcings stand out. I will survey some results concerning such principles, which can be formulated for other classes of forcing as well, in terms of consistency strength calibrations and consequences. The principles include hierarchies of (weak) bounded forcing axioms, (virtual) resurrection axioms, and maximality principles. The weak/virtual principles arise from the original principles, formulated in terms of the existence of elementary embeddings, by requiring only the existence of generic embeddings, and it turns out that the consistency strengths of the arising principles can be determined precisely. The focus in terms of consequences of the principles is on the failure of (weak/threaded) square principles, but I will also mention principles that imply the existence of definable well-orderings of P(ω1). Time permitting, I will also talk about parametric generalizations of subcompleteness, which give rise to classes of forcings that enjoy nice closure properties and come with iteration theorems as well.
  2. Grigor Sargsyan: Universally Baire sets of reals and iteration strategies

    Call a cardinal kappa non-domestic if it is a measurable limit of Woodin cardinals and strong cardinals. We will show that in models of AD^+ that are of the form L(powerset(R)), if HOD doesn't have a non-domestic cardinal then every set of reals is Wadge equivalent to an iteration strategy of a hod mouse. Such representation of sets of reals is needed for many application of the theory of hod mice, including the computation of HOD of models of determinacy and core model induction applications.
  3. John R. Steel: What is a mouse?

    A mouse is an iterable premouse. Or is it? We shall discuss some of the varieties of premice, and the properties that iteration strategies can have. Then we shall suggest a definition of "mouse" in the short-extender realm that differs slightly from the "iterable premouse" formulation.
  4. W. Hugh Woodin: The one generator framework

    We define the one generator framework for fine-structural strategic-extender models. Roughly, the one generator condition is simply the condition that extenders have a largest generator and at most one generator past the shortest initial segment not in their ultrapowers. This turns out to completely dictate essential features of the hierarchy with a number of surprising implications for the long-extender regime past the finite levels of supercompact.

If you wish to register for this conference and you are not a speaker and also not yet listed below as a "registered participant," you are kindly requested to send an email to Ralf Schindler at rds@wwu.de. Deadline for registration: July 14, 2017.

There is no registration fee, but we will ask participants for a small donation in order to cover expenses for coffee, tea, other drinks, and cookies.

We are planning to have a conference dinner in the restaurant Il cucchiaio d'Argento on Aug 03, 2017. If you wish to join us and you are not in the set

A+ = A ∪ partners of A,


A = speakers ∪ organizers ∪ { Ronald Jensen },

then you will have to register for it by sending an email to Marga López Arpí at margarpi@hotmail.com by May 31, 2017 . It won't be possible to register for joining us for the dinner at any later point. Warning: If you are not in the set A, then you should expect that you will have to pay for the dinner by yourself! There will be four choices of menues (meat, fish, vegetarian, vegan) for 30 € each.

Registered participants:

Juan P. Aguilera TU WienDinner: yes
Rachid Atmai Wien Dinner: no
Mariam Beriashvili Tbilisi Dinner: no
Doug Blue Harvard Dinner: yes
Andrés Caicedo AMS Dinner: no
Rupert McCallumTübingen Dinner: yes
Fabiana Castiblanco MünsterDinner: no
Romain Dufêtre HarvardDinner: no
Henry Ehimetalor DenverDinner: no
Qi Feng BeijingDinner: no
Gabriel Fernandes MünsterDinner: yes
Gunter Fuchs CUNYDinner: yes
Gabriel Goldberg HarvardDinner: yes
Moti Gitik Tel AvivDinner: yes
Miha Habič CUNYDinner: no
Yair Hayut HU JerusalemDinner: no
Radek Honzik Charles University, PragueDinner: yes
Ronald Jensen HU BerlinDinner: yes 2x
Asaf Karagila Jerusalem Dinner: yes
Yurii Khomskii AmsterdamDinner: no
Martin Köberl RutgersDinner: yes
Robert Lubarsky Boca RatonDinner: yes
Menachem Magidor HU JerusalemDinner: yes
Adrian Mathias ReunionDinner: yes 2x
Stefan Miedzianowski MünsterDinner: yes
Kaethe Minden CUNYDinner: no
Bill Mitchell GainesvilleDinner: yes 2x
Rahman Mohammadpour ParisDinner: yes
Itay Neeman UCLADinner: yes
Dan Saattrup Nielsen Bristol Dinner: yes
Grigor Sargsyan RutgersDinner: yes
Ralf Schindler MünsterDinner: yes 3x
Philipp Schlicht BonnDinner: yes
Farmer Schlutzenberg MünsterDinner: yes
John Steel UC BerkeleyDinner: yes 2x
Sarka Stejskalova Charles University, PragueDinner: yes
Sandra Uhlenbrock WienDinner: yes
Hugh Woodin HarvardDinner: yes
Shi Xianghui BeijingDinner: yes
Martin Zeman UC IrvineDinner: yes
Yizheng Zhu MünsterDinner: yes

Housing information:

  • airbnb
  • Barbara's bed and breakfast, she has rooms for 25 -- 68 EUR. This is the only one not within walking distance, so you'd need a bike; but it's nice and cheap.
  • Nordstern hostel, rooms for 29 EUR.
  • My bed and breakfast, rooms for 49 -- 69 EUR.
  • Handwerkskammer Münster. They have very nice rooms for less than 100 € per week. Contact: Frau Iris Weverinck-Friedrichs, iris.weverinck@hwk-muenster.de, phone no. +49-251-705-1305.
  • Haus Niemann, rooms for 59,50 EUR.
  • Factory Hotel.
  • Hotel am Schlosspark.
  • Hotel Jellentrup.

  • Travel information:

    Münster has an airport, IATA code: FMO. You may e.g. fly there with Lufthansa (or, United, operated by Lufthansa 😊) via Frankfurt or Munich. A cab from FMO to the center is about 50 €, but there are shuttle buses for about 7 €. Another good option to reach Münster is to fly to Düsseldorf, IATA code: DUS, and take a train from there, which takes about 1 1/2 hours.

    Tourist information:

    The fifth Sculpture Projects Münster, see here, will take place in 2017: Skulptur Projekte.