04/08/30 11:56
>360 (1)
0 = |Σ[k=1,m] x_k↑ |^2 = Σ[k=1,m] |x_k|^2 ＋ Σ[1≦i<j≦m] 2（x_i, x_j）
= Σ[1≦i<j≦m] {|x_i|^2 +|x_j|^2 +2（x_i, x_j）} － (m-2)Σ[k=1,m] |x_k|^2
= Σ[1≦i<j≦m] |x_i +x_j|^2 － (m-2)Σ[k=1,m] |x_k|^2.
04/08/30 11:56
>360 (1)
0 = |Σ[k=1,m] x_k↑ |^2 = Σ[k=1,m] |x_k|^2 ＋ Σ[1≦i<j≦m] 2（x_i, x_j）
= Σ[1≦i<j≦m] {|x_i|^2 +|x_j|^2 +2（x_i, x_j）} － (m-2)Σ[k=1,m] |x_k|^2
= Σ[1≦i<j≦m] |x_i +x_j|^2 － (m-2)Σ[k=1,m] |x_k|^2.