In\"on\"u-Wigner Contraction and $D=2+1$ Supergravity

Abstract

We present a generalization of the standard In\"on\"u-Wigner contraction by rescaling not only the generators of a Lie superalgebra but also the arbitrary constants appearing in the components of the invariant tensor. The procedure presented here allows to obtain explicitly the Chern-Simons supergravity action of a contracted superalgebra. In particular we show that the Poincar\'e limit can be performed to a $D=2+1$ $\left(p,q\right) $ $% AdS$ Chern-Simons supergravity in presence of the exotic form. We also construct a new three-dimensional $\left(2,0\right) $ Maxwell Chern-Simons supergravity theory as a particular limit of $\left(2,0\right) $ $AdS$ -Lorentz supergravity theory. The generalization for $\mathcal{N}=p+q$ gravitini is also considered.