 in the restricted neighborhood ![ $$N\(\(S,\\bar{S}\): \(S^{g},\\bar{S}^{g}\)\) = N^{+}\(\(S,\\bar{S}\): \(S^{g},\\bar{S}^{g}\)\)\\; \\cup \\; N^{-}\(\(S,\\bar{S}\): \(S^{g},\\bar{S}^{g}\)\)$$ ](A000000_0_En_00_Chapter_IEq000.gif) is 