利用投影的对角化,回答了何时C*代数A的商代数M(A)/A上的投影可以提升为M(A)中的投影这一问题,具体给出了两个等价条件:投影的正元提升是弱拟对角的;投影存在形如∞∑i=1ai的正元提升,其中{ai}是两两正交的正元.对一般的商代数A/I,如果投影p,q存在A中提升p1,q1,且满足σ(p1q1p)≠[0,1],那么p,q可以提升成保持其直交性及大小关系的投影.
The paper answers when the projections of algebra M( A )/A can lift to the projection of M( A ) on the basis of diagonalization of projection in M(A ), and gives two equivalent conditions: the positive lift of projection is weakly-quasidiagonal; the projection lifts to positive element of the form ∞∑i=1ai, where {ai} are mutually orthogonal positive elements. For general quotient algebra A/I,if projections p, q lift to p1, q1 such that a(p1 q1P1 )≠[0, 1], then p, q can lift to projections preserving their orthogonality and big and small relations.