设A且是线性序集{1〈2〈…〈n-1〈n}的对偶扩张代数。Г=EndAT是A的Ringel对偶代数,则A的Cartan矩阵的顺序主子式依次为n,n-1,…,2,1,其逆序主子式均为1,而Г的Cartan矩阵的顺序主子式均为1。进一步,A的Cartan矩阵的逆矩阵为三对角M-矩阵,其顺序主子式均为1。
Let A be the dual extension algebra of the linearly ordered set {1〈2〈...〈n-1〈n } and Г = EndA T the Ringel dual of A. Then all the upper-left submatrices of the Cartan matrix of A have determinants n, n - 1 ,... ,2,1 in order, all the lower-right submatrices of the Cartan matrix of A have determinants 1 ; while all the upper-left submatriees of the Cartan matrix of Г have determinants 1. Moreover, the inverse of the Caftan matrix of A is a tridiagonal M-matrix with determinants of all the upper-left submatrices 1.