Being perpendicular to each another, the vectors A and B can be viewed as the principal axes of the conserved tensor W, i.e., its scaled eigenvectors. W is perpendicular to L , L ⋅ ⋅ W = α α ( L ⋅ ⋅ A ) A + β β ( L ⋅ ⋅ B ) B = 0 , since A and B are both perpendicular to L as well, L ⋅ A = L ⋅ B = 0.