Workshop on Proof Theory, Modal Logic and Reflection Principles

Universitat de Barcelona, Spain

November 5-8, 2019

The Wormshop

We are proud to announce the lustrum edition of the international workshop "Proof Theory, Modal Logic and Reflection Principles." The workshop (also known as the "Wormshop") will take place at the University of Barcelona from Tuesday, November 5 until Friday, November 8, 2019.

The tradition of modal logics inspired on the notion of formal proof dates back to Gödel, but their study has gained great momentum in the last decade due to novel applications in the foundations of mathematics. Their study moreover requires the interaction of several disciplines in mathematical logic and beyond, including computational logic, proof theory, and point-set topology.

The aim of this workshop is to bring together experts in relevant fields in order to discuss recent advances and foster new collaborations. Topics include but are not restricted to:

  • Provability logics and algebras
  • Lightweight fragments of modal logics
  • Proof theory and ordinal analysis
  • Weak and strong systems of arithmetic
  • Modalities in topology and set theory
  • Justification logics and logics of proofs
  • Computability and complexity

This edition of the workshop is the fifth in the series. The previous conferences took place in Barcelona (2012), Mexico City (2014), Tbilisi (2016) and Moscow (2017). This year we are returning to our roots in Barcelona to celebrate the lustrum edition, with a stellar lineup of invited speakers from across the globe.


To register please fill out this form.

Regular conference fee: 150 €
Reduced conference fee: 70 €
Minimal conference fee: 35 €


Juan Pablo Aguilera

Anton Freund

Michał Tomasz Godziszewski

Lev Gordeev

Evgeny Kolmakov

Graham E. Leigh

Félix Lara-Martín

Georg Moser

Sam Sanders

Ilja Shapirovsky

Thomas Studer

Mikhail Svyatlovsky

Albert Visser

Gunnar Wilken


To be announced.


Mathematics Building, Room T1

Gran Via de les Corts Catalanes, 585
08007 Barcelona


Bellow are some suggestions of places to stay, at most 15 minutes away by foot.
(Any others with similar characteristics should be fine.)


Program committee
Lev D. Beklemishev

Steklov Institute of Mathematics.

Andrés Cordón Franco

Dept. of Computer Science and Artificial Intelligence, University of Seville.

David Fernández Duque

Dept. of Mathematics, University of Ghent.

Eduardo Hermo Reyes

Dept. of Philosophy, UB.

Joost J. Joosten

Dept. of Philosophy, UB.

Félix Lara-Martín

Dept. of Computer Science and Artificial Intelligence, University of Sevilla.

Andreas Weiermann

Dept. of Mathematics, University of Ghent.

Organizing committee
Joan Bagaria

Dept. of Mathematics and Computer Science, UB, ICREA

Ana de Almeida Borges

Dept. of Philosophy, UB.

Juan José Conejero Rodrı́guez

Dept. of Philosophy, UB.

Mireia González Bedmar

Dept. of Philosophy, UB.

Eduardo Hermo Reyes

Dept. of Philosophy, UB.

Joost J. Joosten (Chair)

Dept. of Philosophy, UB.

Eric Sancho Adamson

Dept. of Philosophy, UB.

Contact information

Artist impression on the worm battle
Andreas Weiermann, 2019


Joost J. Joosten

+34 934 037 984

Carrer de Montalegre, 6
08001 Barcelona

Poster (thanks to Eric Sancho Adamson)