Indecomposable Hopf *-algebra representations with invariant inner product

We generalize a result of Araki (1985) on indecomposable group representations with invariant (necessarily indefinite) inner product and irreducible subrepresentation to Hopf *-algebras. Moreover, we characterize invariant inner products on the projective indecomposable representations of small quantum groups U qsl(2) at odd roots of unity and on the indecomposable representations of generalized Taft algebras H n,d(q) .