Idempotents of the Green algebras of finite dimensionalpointed rank one Hopf algebras of nilpotent type

Abstract

In this paper, we intend to study idempotents of the Green algebra (complexied Green ring) of anynite dimensional pointed rank one Hopf algebra of nilpotent type over the complex numbereld. Werst determine all one dimensional representations of the quotient algebra of the Green algebra modulo its Jacobson radical. This gives rise to all primitive idempotents of the quotient algebra. Then we present explicitly primitive idempotents of the Green algebra by lifting the ones of the quotient algebra. Finally, as an example, we describe all primitive idempotents of the Green algebra of the Taft algebra T3 .