The Cardy-Cartan modular invariant
  Using factorizable Hopf algebras, we construct modular invariant partition functions of charge conjugation, or Cardy, type as characters of coends in categories that share essential features with the ones appearing in logarithmic CFT. The coefficients of such a partition function are given by the Cartan matrix of the theory. 
Jurgen Fuchs, Christoph Schweigert, Carl Stigner
hep-th math.QA