2) If g is an irresolvable Cartan solvable Lie algebra, then of with the Borel subalgebra of the nine typical simple Lie algebra is isomorphism.

• ( ii)若 g是一个不可分解的 Cartan可解李代数 ；则 g与 9种典型单李代数之一的 Borel子代数同构 .