1 1 cele seje ←-(@) 1 Uk= 1 -s j识3 ←-(k) 1 ◆◆· 1 41 2 3 4 1 1 ( ) 1 1 ( ) 1 1 ik j j U j j ce se i k se ce θ θ θ θ =     ← − ←        4