By using the fundamental Lie correspondence, the statements and the reasoning above translate directly to Lie algebras with (abelian) nontrivial non-discrete normal subgroups replaced by (one-dimensional) nontrivial ideals in the Lie algebra, and the center of SO(3; 1) replaced by the center of s l ( 3 ; 1 ) + The center of any semisimple Lie algebra is trivial and s o ( 3 ; 1 ) is semi-simple and simple, and hence has no non-trivial ideals.