WN-空间的可膨胀性

The expandability of WN-space

研究了一个判定WN-空间可膨胀的条件.即在正规空间中,若X是WN-空间且其WN-函数满足条件:如果y∈g(n,x),那么g(n,y)g(n,x),则X是可膨胀的.

A condition is given to determine whether a WN-space is expandable. In a normal space, if X is a WN-space and its WN-function satisfies： for any point y∈g（ n, x）, that g（ n, y） ∈ g（ n, x）, then X is expandable.