摘要
设R是reduced环.记Un(R)为R上的n×n上三角矩阵环.则Un(R)不是半交换环.本文证明了Un(R)的子环Rn是半交换环.作为推论,证明了R平凡扩张T(R,R)也是半交换环.
Let R be a reduced ring.Let U_n(R) denote the ring of all n by n upper triangular matrixs with ertries in R.Then U_n(R) is not a semicommutative ring.It is proved that the subring R_n of U_n(R) is semicommutative ring.As a corollary,it is proved that the trivial extension T(R,R) of R is semicommutative ring.
出处
《甘肃教育学院学报（自然科学版）》
2004年第1期10-12,共3页
Journal of Gansu Education College(Natural Science Edition)
