  Motivated by the orthogonality relations for irreducible characters of a
finite group, we evaluate the sum of a finite group of linear characters of a
Hopf algebra, at all grouplike and skew-primitive elements. We then discuss
results for products of skew-primitive elements. Examples include groups,
(quantum groups over) Lie algebras, the small quantum groups of Lusztig, and
their variations (by Andruskiewitsch and Schneider).
