Equation Icon  [ ] H⊥-(z) −-H-||(z) ---------1-−-H-||(z)∂z-(1-+-z)DA-(z)------------ 𝜀 = 2H ⊥ + H || ≃ ( [ ] ). (4.4.4 ) 3H ||(z)DA (z) + 2 1 − H ||(z )∂z (1 + z )DA (z )