  Pure backgrounds are a natural generalization of supersymmetric Calabi-Yau
compactifications in the presence of flux. They are described in the language
of generalized SU(d) x SU(d) structures and generalized complex geometry, and
they exhibit some interesting general patterns: the internal manifold is
generalized Calabi-Yau, while the Ramond-Ramond flux is exact in a precise
sense discussed in this paper. We have shown that although these two
characteristics do persist in the case of generic ten-dimensional Euclidean
type II pure backgrounds, they do not capture the full content of
supersymmetry. We also discuss the uplift of real Euclidean type IIA pure
backgrounds to supersymmetric backgrounds of Lorentzian eleven-dimensional
supergravity.
