1. Workshop on Algebraic Surfaces (March 1-2, 2018; with Brandhorst, Gonzalez Alonso)
  2. Workshop New Trends in Arithmetic and Geometry of Algebraic Surfaces at BIRS (March 12-17, 2017; with Elkies, Oguiso)
  3. Workshop on algebraic surfaces at Leibniz Universität Hannover (Sept 15/16, 2016; with Gonzalez-Alonso)
  4. Conference Algebraic Geometry at Leibniz Universität Hannover (July 13-16, 2016; with Farkas, Hulek, Müller-Stach)
  5. Workshop Calabi-Yau varieties: Arithmetic, geometry and physics at Herstmonceux Castle (June 20-26, 2016; with Gross, Laza, Yui)
  6. Arithmetic Geometry Days at Københavns Universitet (Nov 12/13, 2015; with Halle, Kiming)
  7. Workshop Explicit methods for modularity of K3 surfaces and other higher weight motives at ICERM (Oct 19-24, 2015; with Rodriguez-Villegas, Swisher, Tschinkel, Viray, Voight)
  8. Workshop on geometry and arithmetic of hyperkähler manifolds at Leibniz Universität Hannover (Feb 9-11, 2015; with Chr. Lehn)
  9. Arithmetic and Algebraic Geometry 2015 at Tokyo University (Jan 27-31, 2015; with Katsura, Kondo, Moriwaki, Mukai, Nakamura, Terasoma)
  10. Algebraic Geometry Session at joint DMV-PTM meeting in Poznan (Sept 17-19, 2014; with Cynk, Müller-Stach, Szemberg)
  11. Major Thematic Program Calabi-Yau Varieties: Arithmetic, Geometry and Physics at the Fields Institute, Toronto (July - December, 2013; with M. Gross, S. Gukov, R. Laza, J. Walcher, S.-T. Yau, N. Yui)
  12. Workshop on Algebraic Surfaces at Leibniz Universität Hannover (October 2, 2013)
  13. Conference Nouvelles directions en arithmetique et geometrie des surfaces algebriques at CIRM in Luminy (March 11-15, 2013; with Bert van Geemen, A. Sarti, T. Shioda)
  14. Conference on Algebraic and Complex Geometry at Leibniz Universität Hannover (September 10-14, 2012; with A. Frühbis-Krüger, R. Kloosterman) 
  15. Workshop on Algebraic Surfaces at Leibniz Universität Hannover (February 03, 2012)
  16. Workshop on Singularities and Monodromy at Leibniz Universität Hannover (October 6-7, 2011; with A. Frühbis-Krüger, M. Lönne)
  17. Workshop on Arithmetic and Geometry of K3 surfaces and Calabi-Yau threefolds at the Fields Institute, Toronto (Aug 16-25, 2011; with C. Doran, S. Kondo, R. Laza, J. Lewis, N. Yui)
  18. Workshop on Elliptic fibrations and K3 surfaces at Humboldt-Universität Berlin (July 14-16, 2010; with R. Kloosterman)
  19. Workshop on Arithmetic aspects of elliptic surfaces at Hausdorff Institute for Mathematics (March 11 & 12, 2010; with Cecilia Salgado)