Dyer-Lashof-Cohen operations in Hochschild cohomology
It is already well known that Hochschild cohomology complex is endowed with an
action of an operad quasi-isomorphic to the chains operad of little squares. It means
in particular that Hochschild cohomology has the same operations as the homology of
double loop spaces. For instance, cup-product corresponds to Pontriagyn product,
Gerstenhaber bracket corresponds to the Browder operator. We will present
explicit formulae for unary Hochschild cohomology operations analogous to
operations ξ1 and ζ1 introduced by Araki-Kudo for p = 2 and by F.Cohen for
p > 2.
