*** Call for participation*** Caleidoscope: Research School in Computational Complexity Institut Henri Poincaré, Paris, 17-21 June 2019 http://caleidoscope.sciencesconf.org/ Dear all, This is the second announcement for the Caleidoscope Research School in Computational Complexity, to take place at the Institut Henri Poincaré, Paris 17-21 June 2019. The school is aimed at graduate students and researchers who already work in some aspects of computational complexity and/or who would like to learn about the various approaches. *Important news:* - the registration deadline is set to *19 May 2019*; - we are now accepting applications for *financial support* for participants (see below for the details). DESCRIPTION Computational complexity theory was born more than 50 years ago when researchers started asking themselves what could be computed efficiently. Classifying problems/functions with respect to the amount of resources (e.g. time and/or space) needed to solve/compute them turned out to be an extremely difficult question. This has led researchers to develop a remarkable variety of approaches, employing different mathematical methods and theories. The future development of complexity theory will require a subtle understanding of the similarities, differences and limitations of the many current approaches. In fact, even though these study the same phenomenon, they are developed today within disjoint communities, with little or no communication between them (algorithms, logic, programming theory, algebra...). This dispersion is unfortunate since it hinders the development of hybrid methods and more generally the advancement of computational complexity as a whole. The goal (and peculiarity) of the Caleidoscope school is to reunite in a single event as many different takes on computational complexity as can reasonably be fit in one week. It is intended for graduate students as well as established researchers who wish to learn more about neighbouring areas. LECTURES 1. Boolean circuits and lower bounds. (Rahul Santhanam, University of Oxford) 2. Algebraic circuits and geometric complexity. (Peter Bürgisser, Technical University Berlin) 3. Proof complexity and bounded arithmetic. (Sam Buss, University of California San Diego) 4. Machine-free complexity (descriptive and implicit complexity). (Anuj Dawar, University of Cambridge and Ugo Dal Lago, University of Bologna) In addition to these broad-ranging themes, there will also be three more focussed topics, providing examples of (already established or potential) interactions between logic, algebra and complexity: 5. Constraint satisfaction problems. (Libor Barto, Charles University in Prague) 6. Communication complexity. (Sophie Laplante, Paris 7 University) 7. Duality in formal languages and logic. (Daniela Petrisan, Paris 7 University) REGISTRATION Registration to the school is free but mandatory. This is to help us plan tea/coffee breaks and social activities. https://caleidoscope.sciencesconf.org/registration/index The deadline for registration is *19 May 2019*. FINANCIAL SUPPORT Financial support is available for participants. You may apply by filling in the following online form: http://tiny.cc/0oi33y Please send your application no later than *14 April 2019* to maximize your chances of being considered. (Our funds being limited, we apologize in advance if your support request will only be met partially or declined). Also note that *student* members of the ASL (Association for Symbolic Logic) may apply for travel support (not lodging!) by contacting directly ASL and mentioning attendance to Caleidoscope (which is sponsored by ASL). SPONSORS Funding sponsors: DIM RFSI - Région Île-de-France (https://dim-rfsi.fr/) Agence Nationale de la Recherche (http://www.agence-nationale-recherche.fr/) CNRS (http://www.cnrs.fr/en) SIGLOG (https://siglog.hosting.acm.org/) The European Commission (https://ec.europa.eu/commission/index_en) Université Paris 13 (https://www.univ-paris13.fr/) Laboratoire d'Informatique de Paris Nord (https://lipn.univ-paris13.fr/) Association for Symbolic Logic (http://aslonline.org/) Other sponsors: European Association for Computer Science Logic (http://www.eacsl.org/) Société Mathématique de France (https://smf.emath.fr/)