Equation Icon  ( ) A Γ X = Γ † B where A = − A† ∈ ℂp×p, B = − B † ∈ ℂq×q, (6.92 ) Tr A + TrB = 0, Γ ∈ ℂp×q with p = 3 (respectively 4) and q = 2 (respectively 1).