Equation Icon  0 1 -ζ +-ζ¯ 2 1--ζ −-¯ζ- 3 1-−-ζ-¯ζ W = 1, W = 1 + ζ¯ζ, W = i1 + ζ¯ζ, W = 1 + ζ ¯ζ. (6.3 )