Mirror symmetry and Arnold's duality.
Moduli of simple Rank-2 sheaves on K3-surfaces.
Moduli stacks of polarized K3 surfaces in mixed characteristic
2000 Mathematics Subject Classification: 14J28, 14D22.In this note we define moduli stacks of (primitively) polarized K3 spaces. We show that they are representable by Deligne-Mumford stacks over Spec(Z). Further, we look at K3 spaces with a level structure. Our main result is that the moduli functors of K3 spaces with a primitive polarization of degree 2d and a level structure are representable by smooth algebraic spaces over open parts of Spec(Z). To do this we use ideas of Grothendieck, Deligne,...