This short exposition is about some commutativity conditions on a semiprime right Goldie Ck-ring. In particular, it is o......

<正> 在[1][2]中许永华对结合环R引入右R-模同态链归纳条件,可以叙述为:设r∈R,令元素r的右零化子r~⊥={x∈R|rx=0}。设M={r~⊥,AO......