置换空间上的滴性和弱滴性

摘要

In this paper we will give the following results: PXXn has drop (weak drop) properties if and only if each Xn (n=1,2,...) has drop (weak drop) properties too.%主要给出下面结果. 即PXXn具有滴性和弱滴性的充分必要条件是每个Xn具有滴性和弱滴性条件.