A formal group-analog of the Brauer group. The special case of the concept of Artin-Mazur formal group for $n = 2$. The $n = 1$-analog is the formal Picard group.
In higher dimensional analogy of how the formal Picard group of an elliptic curve gives the formal group of an elliptic spectrum representing an elliptic cohomology theory, so the formal Brauer group of a K3 surface gives the formal group of an complex oriented cohomology theory given by a spectrum hence called a K3-spectrum representing K3-cohomology.
moduli spaces of line n-bundles with connection on $n$-dimensional $X$
The original account of the construction of formal Picard groups is
Modern reviews include
Markus Szymik, section 3 of K3 spectra (pdf)
Christian Liedtke, around p. 40 of Lectures on Supersingular K3 Surfaces and the Crystalline Torelli Theorem (arXiv.1403.2538)
Last revised on May 21, 2014 at 21:23:58. See the history of this page for a list of all contributions to it.