Bloch's formula

In algebraic K-theory, a branch of mathematics, Bloch's formula, introduced by Spencer Bloch for K2, states that the Chow group of a smooth variety X over a field is isomorphic to the cohomology of X with coefficients in the K-theory of the structure sheaf 𝒪X; that is,

CHq(X)=Hq(X,Kq(𝒪X))

where the right-hand side is the sheaf cohomology; Kq(𝒪X) is the sheaf associated to the presheaf U↦Kq(U), U Zariski open subsets of X. The general case is due to Quillen. For q = 1, one recovers Pic⁡(X)=H1(X,𝒪X∗). (see also Picard group.)

The formula for the mixed characteristic is still open.

See also

References

  1. ↑ For a sketch of the proof, besides the original paper, see http://www-bcf.usc.edu/~ericmf/lectures/zurich/zlec5.pdf Archived 2013-12-15 at the Wayback Machine