<p>The eccentricity matrix <InlineEquation ID="IEq3"> <EquationSource Format="TEX">\(\epsilon (G),\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi>ϵ</mi> <mo stretchy="false">(</mo> <mi>G</mi> <mo stretchy="false">)</mo> <mo>,</mo> </mrow> </math></EquationSource> </InlineEquation> of a connected graph <i>G</i> is obtained by retaining the maximum distance from each row and column of the distance matrix of <i>G</i>, and the other entries are assigned with 0. In this paper, we discuss the eccentricity spectrum of the subdivision vertex (edge) join of regular graphs. Also, we obtain new families of graphs having irreducible or reducible eccentricity matrix. Furthermore, we use these results to construct infinitely many <InlineEquation ID="IEq4"> <EquationSource Format="TEX">\(\epsilon \)</EquationSource> <EquationSource Format="MATHML"><math> <mi>ϵ</mi> </math></EquationSource> </InlineEquation>-cospectral graph pairs as well as infinitely many pairs and triplets of non <InlineEquation ID="IEq5"> <EquationSource Format="TEX">\(\epsilon \)</EquationSource> <EquationSource Format="MATHML"><math> <mi>ϵ</mi> </math></EquationSource> </InlineEquation>-cospectral <InlineEquation ID="IEq6"> <EquationSource Format="TEX">\(\epsilon \)</EquationSource> <EquationSource Format="MATHML"><math> <mi>ϵ</mi> </math></EquationSource> </InlineEquation>-equienergetic graphs. Moreover, we present some new family of <InlineEquation ID="IEq7"> <EquationSource Format="TEX">\(\epsilon \)</EquationSource> <EquationSource Format="MATHML"><math> <mi>ϵ</mi> </math></EquationSource> </InlineEquation>-integral graphs.</p>

错误:搜索内容不能为空,请输入英文关键词
错误:关键词超出字数限制,请精简
高级检索

On irreducibility of eccentricity matrix of graphs and construction of \(\epsilon \)-equienergetic graphs

  • Anjitha Ashokan,
  • Chithra A. V.

摘要

The eccentricity matrix \(\epsilon (G),\) ϵ ( G ) , of a connected graph G is obtained by retaining the maximum distance from each row and column of the distance matrix of G, and the other entries are assigned with 0. In this paper, we discuss the eccentricity spectrum of the subdivision vertex (edge) join of regular graphs. Also, we obtain new families of graphs having irreducible or reducible eccentricity matrix. Furthermore, we use these results to construct infinitely many \(\epsilon \) ϵ -cospectral graph pairs as well as infinitely many pairs and triplets of non \(\epsilon \) ϵ -cospectral \(\epsilon \) ϵ -equienergetic graphs. Moreover, we present some new family of \(\epsilon \) ϵ -integral graphs.