令A是一个C^*-代数.设(x,y)是A的Cuntz半群W(A)中的一个元素对.本文在适当的条件下具体刻画了所有的(x,y),使其满足性质:如果x≤y,那么存在z∈W(A)使得x+z=y,另外,本文还讨论了交换C^*-代数关于Cuntz比较的一些性质.
Let A be a C^*-algebra. In this paper, we present some necessary and suiffcient conditions for the pair (x, y) of elements in the Cuntz semigroup W(A) of A such that if x ≤ y, then x + z = y for some z ∈ W(A), in the case of certain C^*-algebras. In addition, some properties about the Cuntz comparison in commutative C^*-algebras are obtained.