图 G 的批评的组 C (G) 是跨越图的树的数字的精炼并且仔细与拉普拉斯算符矩阵被连接。让 r (G) 是发电机的最小的数字(即，等级) 组 C，(G) 和(G) 是 G 的独立周期的数字。在这份报纸，某禁止的导致的 subgraphs 为 r (G)= n 被给 3 并且有 r (G)=(G)= n 的所有图 3 被描绘。
In this paper, we introduce the m-Cartan matrix and observe that some properties of the quadratic form associated to the Cartan matrix of an Euclidean diagram can be generalized to the m-Cartan matrix of a McKay quiver. We also describe the McKay quiver for a finite abelian subgroup of a special linear group.
GUO JinYun School of Mathematics and Computational Sciences, Xiangtan University, Xiangtan 411105, China
In this paper the sufficient and necessary conditions are given for a for- mal triangular matrix ring to be right PP,generalized right PP,or semihereditary, respectively.
