On the adjacency matrix of a block graph

被引:16
作者
Bapat, R. B. [1 ]
Roy, Souvik [2 ]
机构
[1] Indian Stat Inst, Stat Math Unit, New Delhi 110016, India
[2] Indian Stat Inst, Econ & Planning Unit, New Delhi 110016, India
关键词
block graph; adjacency matrix; determinant; tree; line graph; 15A15; 05C05; TREES;
D O I
10.1080/03081087.2013.779268
中图分类号
O1 [数学];
学科分类号
0701 ; 070101 ;
摘要
A block graph is a graph in which every block is a complete graph. Let G be a block graph and let A be the adjacency matrix of G. We first obtain a formula for the determinant of A over reals. It is shown that A is nonsingular over F2 if and only if the removal of any vertex from G produces a graph with exactly one odd component. A formula for the inverse of A over F2 is obtained, whenever it exists. We obtain some results for the adjacency matrices over F2, of claw-free block graphs, which are the same as the line graphs of trees, and for the adjacency matrices of flowers, which are block graphs with only one cut-vertex.
引用
收藏
页码:406 / 418
页数:13
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