Universal Enveloping Algebra and Differential Calculi on Orthogonal q-groups

We review the construction of the multiparametric quantum group $ISO_{q,r}(N)$ as a projection from $SO_{q,r}(N+2)$ and show that it is a bicovariant bimodule over $SO_{q,r}(N)$. The universal enveloping algebra $U_{q,r}(iso(N))$, characterized as the Hopf algebra of regular functionals on $ISO_{q,r}(N)$, is found as a Hopf subalgebra of $U_{q,r}(so(N+2))$ and is shown to be a bicovariant bimodule over $U_{q,r}(so(N))$. An R-matrix formulation of $U_{q,r}(iso(N))$ is given and we prove the pairing $U_{q,r}(iso(N))\leftrightarrow ISO_{q,r}(N)$. We analyze the subspaces of $U_{q,r}(iso(N))$ that define bicovariant differential calculi on $ISO_{q,r}(N)$.