Gauge theories of quantum groups
  We find two different q-generalizations of Yang-Mills theories. The corresponding lagrangians are invariant under the q-analogue of infinitesimal gauge transformations. We explicitly give the lagrangian and the transformation rules for the bicovariant q-deformation of $SU(2) \times U(1)$. The gauge potentials satisfy q-commutations, as one expects from the differential geometry of quantum groups. However, in one of the two schemes we present, the field strengths do commute. 
Leonardo Castellani