Brauer Groups and Obstruction Problems : Moduli Spaces and Arithmetic The contributions in this book explore various contexts in which the derived category of coherent sheaves on a variety determines some of its arithmetic. This setting provides new geometric tools for interpreting elements of the Brauer group. With a view towards future arithmetic applications the book extends a number of powerful tools for analyzing rational points on elliptic curves e.g. isogenies among curves torsion points modular curves and the resulting descent techniques as well as higher dimensional varieties like K3 surfaces. Inspired by the rapid recent advances in our understanding of K3 surfaces the book is intended to foster cross pollination between the fields of complex algebraic geometry and number theory. Contributors: · Nicolas Addington · Benjamin Antieau · Kenneth Ascher · Asher Auel · Fedor Bogomolov · Jean Louis Colliot Thélène · Krishna Dasaratha · Brendan Hassett · Colin Ingalls · Martí Lahoz · Emanuele Macrì · Kelly McKinnie · Andrew Obus · Ekin Ozman · Raman Parimala · Alexander Perry · Alena Pirutka · Justin Sawon · Alexei N. Skorobogatov · Paolo Stellari · Sho Tanimoto · Hugh Thomas · Yuri Tschinkel · Anthony Várilly Alvarado · Bianca Viray · Rong Zhou The Brauer group is not a derived invariant Twisted derived equivalences for affine schemes Rational points on twisted K3 surfaces and derived equivalences Universal unramified cohomology of cubic fourfolds containing a plane Universal spaces for unramified Galois cohomology Rational points on K3 surfaces and derived equivalence Unramified Brauer classes on cyclic covers of the projective plane Arithmetically Cohen Macaulay bundles on cubic fourfolds containing a plane Brauer groups on K3 surfaces and arithmetic applications On a local global principle for H3 of function fields of surfaces over a finite field Cohomology and the Brauer group of double covers