where D (Λ) is a finite-dimensional representation, in other words a (2 s + 1)×(2 s + 1) square matrix . Again, ψ is thought of as a column vector containing components with the (2 s + 1) allowed values of σ. The quantum numbers s and σ as well as other labels, continuous or discrete, representing other quantum numbers are suppressed. One value of σ may occur more than once depending on the representation.