马丁公理的两个应用

TWO APPLICATIONS OF MARTIN AXIOM

在MA+7CH下证明了:1.正规空间在有限到一闭映射下的逆象未必正规;2.具有严格正的正则有限Bord测度的拓扑空间具有Caliber(?).

It is proved, under MA+CH, that the inverse image of a normal space under a two to one closed mapping is not necessarily normal and that each topological space with a strictly positive regular finite Borel measure has calibre 1.