A method to find generators of a semi-simple Lie group via the topology of its flag manifolds

Abstract

In this paper we continue to develop the topological method to get semigroup generators of semi-simple Lie groups. Consider a subset $$\Gamma \subset G$$ that contains a semi-simple subgroup $$G_{1}$$ of G. If one can show that $$ \Gamma $$ does not leave invariant a contractible subset on any flag manifold of G, then $$\Gamma $$ generates G if $$\mathrm {Ad}\left( \Gamma \right) $$ generates a Zariski dense subgroup of the algebraic group $$\mathrm {Ad}\left( G\right) $$ . The proof is reduced to check that some specific closed orbits of $$G_{1}$$ in the flag manifolds of G are not trivial in the sense of algebraic topology. Here, we consider three different cases of semi-simple Lie groups G and subgroups $$G_{1}\subset G$$ .