De-equivariantization of Hopf algebras

Abstract

We study the de-equivariantization of a Hopf algebra by an affine group scheme and we apply Tannakian techniques in order to realize it as the tensor category of comodules over a coquasi-bialgebra. As an application we construct a family of coquasi-Hopf algebras $A(H,G,\Phi )$ attached to a coradically-graded pointed Hopf algebra $H$ and some extra data.