2 + 1 kinematical expansions: from Galilei to de Sitter algebras
2 + 1 kinematical expansions: from Galilei to de Sitter algebras
Expansions of Lie algebras are the opposite process of contractions.Starting from a Lie algebra, the expansion process goes to another one, nonisomorphic and less abelian.We propose an expansion method based in the Casimir invariants of the initial and expanded algebras and where the free parameters involved in the expansion are …