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.