选择定理 HUi =Eyi E≤E1≤E,≤E2≤ (v,)=o∑|v,v|=1 The min imum of(u, Hu/y, u)is (Eo, ify can be any state (El, ify can be any state that satisfies condition (V,yo=0 (3)选择定理 (3).... ( , ) 0; (2) , (1) , ; )/( , ) ˆ min ( , ( , ) 1 .... 0 1 0 0 1 2 3 = = =     =                 condition E if can be any state that satisfies E if can be any state The imum of H is E E E E H E i j i j i i i i i