Graphs with two main and two plain eigenvalues
نویسندگان
چکیده
منابع مشابه
Unicyclic graphs with exactly two main eigenvalues
An eigenvalue of a graph G is called a main eigenvalue if it has an eigenvector the sum of whose entries is not equal to zero, and it is well known that a graph has exactly one main eigenvalue if and only if it is regular. In this work, all connected unicyclic graphs with exactly two main eigenvalues are determined. c © 2006 Elsevier Ltd. All rights reserved.
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where ni = nβ 2 i (i = 1, 2); β1 and β2 denote the main angles of μ1 and μ2, respectively. Further, let G be any connected or disconnected graph (not necessarily with two main eigenvalues). Let S be any subset of the vertex set V (G) and let GS be the graph obtained from the graph G by adding a new vertex x which is adjacent exactly to the vertices from S. If σ(GS1) = σ(GS2) then we prove that ...
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ژورنال
عنوان ژورنال: Applicable Analysis and Discrete Mathematics
سال: 2017
ISSN: 1452-8630,2406-100X
DOI: 10.2298/aadm1702244h