完全多部图的无符号Laplacian特征多项式(英文)

For a simple graph G,let matrix Q（G）=D（G） + A（G） be it’s signless Laplacian matrix and Q G （λ）=det（λI Q） it’s signless Laplacian characteristic polynomial,where D（G） denotes the diagonal matrix of vertex degrees of G,A（G） denotes its adjacency matrix of G.If all eigenvalues of Q G （λ） are integral,then the graph G is called Q-integral.In this paper,we obtain that the signless Laplacian characteristic polynomials of the complete multi-partite graphs G=K（n₁,n₂,···,n_t）.We prove that the complete t-partite graphs K（n,n,···,n）t are Q-integral and give a necessary and sufficient condition for the complete multipartite graphs K（m,···,m）s（n,···,n）t to be Q-integral.We also obtain that the signless Laplacian characteristic polynomials of the complete multipartite graphs K（m,···,m,）s1（n,···,n,）s2（l,···,l）s3.     

完全多部图K_(a_1n_1,a_2n_2,…,a_sn_s)的拉普拉斯谱

研究Laplace整图的存在性问题,通过研究完全多部图K_(a_1n_1,a_2n_2,…a_sn_s)的Laplace特征多项式,得到所有完全多部图K_(a_1n_1,a_2n_2,…a_sn_s)都是拉普拉斯整图.     

新的Q整图类K_n~(-tk2)

在他人研究整图,Laplace整图和Seidel-整图的基础上,刻画了Q整图新类.对图类K-tk2n的无符号拉普拉斯特征多项式进行研究分析,应用矩阵的初等变换,给出了图类K-tk2n是Q整图的充分必要条件,得到了新的Q整图类K-tk2n及其Q谱.