The theory of torsors and linear algebraic groups ober arbitrary fields is a well-established area of modern mathematics. It studies the so-called twisted forms of algebraic objects (groups or homogeneous spaces) and has many applications in algebraic geometry, group theory and number theory. The theory of motives and cohomological invariants provides an important tool to classify torsors and linear algebraic groups. The purpose of the workshop is to bring together specialists and young researchers from these areas to discuss recent developments and results, to provide an overview of the current research and applications, and to stimulate new advances.

A special feature of this workshop are 5 mini-courses (5 lectures each) which provide an introduction to the workshop's theme from different perspectives. While introductory, these courses will lead the audience to a survey of the present state of the art:

• Exceptional isomorphisms, triality, and applications to central simple algebras with involution by Anne Quéguiner-Mathieu
• Introduction to Chow groups and Chow motives by Stefan Gille
• Local-global principles in the theory of linear algebraic groups by Julia Hartmann
• Motives and algebraic cycles on twisted flag varieties by Kirill Zainoulline
• An introduction to the theory of essential dimension by Zinovy Reichstein

Besides the mini-courses, we plan to have several lecture series (2 lectures each) on various topics in the direction of the program aimed at post-docs and researchers:

• Cohomological invariants for exceptional groups by S. Garibaldi
• Patching and a local-global principle by D. Krashen
• Torsors over a general base by B. Calmes