“…A large number of nontrivial examples of Frobenius algebras is provided by so-called Schellekens algebras [9,6]; as objects they are direct sums of invertible objects, and they are classified in terms of the cohomology of the Picard group (the group of isomorphism classes of invertible objects) of C and of its subgroups. For a Frobenius algebra, any left module (Ṁ , ρ) gives rise to a left comodule (and vice versa), namely (Ṁ , ̺) with ̺ := (idȦ ⊗ ρ) • ((∆•η) ⊗ idṀ ).…”