A CHARACTERIZATION OF SIGNED GRAPHS REPRESENTED BY ROOT-SYSTEM D-INFINITY

被引：7

作者：

CHAWATHE, PD

VIJAYAKUMAR, GR

机构：

[1] UNIV BOMBAY,DEPT MATH,BOMBAY 400098,INDIA

[2] TATA INST FUNDAMENTAL RES,SCH MATH,BOMBAY 400005,INDIA

来源：

EUROPEAN JOURNAL OF COMBINATORICS | 1990年 / 11卷 / 06期

关键词：

D O I：

10.1016/S0195-6698(13)80037-6

中图分类号：

O1 [数学];

学科分类号：

0701 ; 070101 ;

摘要：

As a consequence of the well known result that a sigraph with least eigenvalue ⩾ −2 is represented by one of the root systems Dn, n ∈ ℕ or E8, these systems have gained importance in the study of the family of sigraphs with all eigenvalues ⩾ − 2. Using a concept called symmetry of sigraphs, we present a new characterization of the family of sigraphs represented by Dn, n ∈ ∕ and compute the class of its minimal forbidden sigraphs. The number of sigraphs in this class, up to switching equivalence, is 49, and any sigraph in this class has at most six vertices. © 1990, Academic Press Limited. All rights reserved.

引用

页码：523 / 533

页数：11

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