给出了三阶矩阵代数M3(C)的上三角子代数A上的双线性映射是2-上循环的等价刻画,然后根据此定理给出了一个映射不是2-上循环的例子.
In this paper, we present the sufficient and necessary conditions that a bilinear mapping on an upper triangular subalgebra of the algebra is a 2-cocycle, then give an example.