A new look at Lie algebras

Abstract

We present a new look at description of real finite-dimensional Lie algebras. The basic element turns out to be a pair $(F,v)$ consisting of a linear mapping $F\in End(V)$ and its eigenvector $v$. This pair allows to build a Lie bracket on a dual space to a linear space $V$. This algebra is solvable. In particular, when $F$ is nilpotent, the Lie algebra is also nilpotent. We show that these solvable algebras are the basic bricks of the construction of all other Lie algebras. %Which allows, having a collection of pairs $(F_i,v_i)$, $i=1, \dots, n$, to construct any Lie algebra. Using relations between the Lie algebra, the Lie--Poisson structure and the Nambu bracket, we show that the algebra invariants (Casimir functions) are solutions of an equation which has a geometric sense. Several examples illustrate the importance of these constructions.