The international workshop “Proof Theory, Modal Logic and Reflection Principles”, also known as the “Wormshop”, will take place at Steklov Institute of Mathematics in Moscow, Russia, from 17.10.2017 to 20.10.2017.

In recent years an approach has been developed for the ordinal analysis of formal theories, based on the study of modal properties of reflection principles. This approach requires techniques from many disciplines; 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
- Turing-Feferman progressions
- Weak fragments of modal logics
- Proof theory and ordinal analysis
- Fragments of first-order arithmetic
- Modalities in topology and set theory
- Axiomatic theories of truth

The workshop is the 4-th conference in the series. The previous conferences took place in Barcelona (2012), Mexico City (2014) and Tbilisi (2016).

Program committee:

- Lev Beklemishev
- David Fernández-Duque
- Joost Joosten
- Fedor Pakhomov

Organizing committee:

- Stepan Kuznetsov
- Fedor Pakhomov
- Daniyar Shamkanov