论文标题
在四个子环的工会上
On rings as unions of four subrings
论文作者
论文摘要
关联环$ r $的覆盖量是其工会为$ r $的适当子环的数量。我们建立了一种对给定有限覆盖号码的Unital环进行分类的策略，并获得覆盖号为四个的Unital环的分类。在此过程中，我们计算每个有限的本地环的覆盖量，其残留场具有主要顺序。
The covering number of an associative ring $R$ is the minimal number of proper subrings whose union is $R$. We establish a strategy to classify unital rings of a given finite covering number, and obtain a classification of unital rings whose covering number is four. Along the way we compute the covering number of every finite local ring whose residue field has prime order.
