Abelian Adjoint representation Borel subalgebra Cartan decomposition Cartan subalgebra Casimir element Completely reducible Derived algebra Dominant integral weights Harish-Chandra homomorphism Height of a root Highest weight modules Indecomposable Integral weight lattice Irreducible algebra Killing form Maximal toral subalgebra Nilpotent algebra Nilpotent element Nilpotent ideal Nilpotent matrices PBW basis Parabolic subalgebra Positive system of roots Reductive subalgebra Root lattice Root space Root space decomposition Root string Root system Semisimple lie algebra Semisimple matrices Simple algebra Simple reflections Simple root Simple system of roots Solvable algebra Standard Borel subalgebra Toral subalgebra Universal enveloping algebra Verma modules Weight module Weight vector Weight space Weights Weyl chamber Weyl vector Weyl group Weyl's complete reducibility theorem Generator of a module Locally finite Maximal vector Schur's Lemma Frobenius Reciprocity Exact functor