Casimir 1931 element of universal enveloping algebra commuting with all generators of a Lie algebra; quadratic Casimir C2 = sum_i T^a T_a; eigenvalue labels irreducible representations.
Casimir 1931 element of universal enveloping algebra commuting with all generators of a Lie algebra; quadratic Casimir C2 = sum_i T^a T_a; eigenvalue labels irreducible representations.