DUALITY FOR A LORENTZ QUANTUM GROUP

We give the algebra L(q) dual to the matrix Lorentz quantum group L(q ) of Podles-Woronowicz, and Watamura et al. As a commutation algebra, it has the classical form L(q) congruent-to U(q)(s1(2, C)) X U(q)(s1( 2, C)). However, this splitting is not preserved by the coalgebra stru cture which we also give. For the derivation, we use a generalization of the approach of Sudbery, viz. tangent vectors at the identity.