Suppose that N is admissible and U is a weakly closed Alg(N)-module. It is shown that there exist unitary operators in U if and only if I- = I and for any N > 0, N- > 0.

• 假设套N是可接受的；则得到弱闭Alg(N)-模u中存在酉算子的充要条件是I-=I且对任意 M>0；有N->0.