Einstein-Hilbert action with cosmological term from Chern-Simons gravity

Understand

We propose a modification to the Lie algebra $S$-expansion method.

• The modification is carried out by imposing a condition on the $S$-expansion procedure, when the semigroup is given by a cyclic group of even order.
• The $S$-expanded algebras are called $S_{H}$-expanded algebras where $S=Z_{2n}$.
• The invariant tensors for $S_{H}$-expanded algebras are calculated and the dual formulation of $S_{H}$-expansion procedure is proposed.