Suppose A1 and A2 are maximal abelian subalgebras of M1 and M2 respectively. Let EAi be the trace preserving conditional expectation of Mi onto Ai (i = 1,2).

• 假设A_1和A_2分别是M_1和M_2的极大交换子代数；E_(Ai)是由M_i到A_i 的保迹的条件期望(i=1；2).