设R为一个环,S是R的非空子集.证明了如下结果:1)设R为Abel环,a∈Cs(R).若a在R中是von Neumann正则元,则a在Cs(R)中也是von Neumann正则元;2)设E(R) S,且R为von Neumann正则环,贝Us(R)是von Neumann正则环;3)设E(R) S,且尺为VNL环,则R不能表示成理想的直和当且仅当Gs(R)为局部环.
Let R be a ring andφ≠S R, it is shown that: 1) If R is an Abelian ring, a∈Cs(R) and a is a von Neumann regular element in R, then a is avon Neumann regular element in Cs(R) ; 2) If E(R) S and R is a von Neumann regular ring, then Cs(R) is also a von Neumann regular ring; 3) If E(R) S and R is a VNL ring, then R can not be written as a direct sum of ideals if and only if Cs (R) is a local ring.