The Average Eccentricity of Block Graphs: A Block Order Sequence Perspective

A graph is a <i>block graph</i> if its blocks are all cliques. In this paper, we study the average eccentricity of block graphs from the perspective of <i>block order sequences</i>. An equivalence relation is established under the block order sequence and used to prove the lo...

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Main Authors: Xingfu Li, Guihai Yu, Kinkar Chandra Das
Format: Article
Language:English
Published: MDPI AG 2022-03-01
Series:Axioms
Subjects:
Online Access:https://www.mdpi.com/2075-1680/11/3/114
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author Xingfu Li
Guihai Yu
Kinkar Chandra Das
author_facet Xingfu Li
Guihai Yu
Kinkar Chandra Das
author_sort Xingfu Li
collection DOAJ
description A graph is a <i>block graph</i> if its blocks are all cliques. In this paper, we study the average eccentricity of block graphs from the perspective of <i>block order sequences</i>. An equivalence relation is established under the block order sequence and used to prove the lower and upper bounds of the eccentricity on block graphs. The result is that the lower and upper bounds of the average eccentricity on block graphs are 1 and <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mfrac><mn>1</mn><mi>n</mi></mfrac><mrow><mo>⌊</mo><mfrac><mn>3</mn><mn>4</mn></mfrac><msup><mi>n</mi><mn>2</mn></msup><mo>−</mo><mfrac><mn>1</mn><mn>2</mn></mfrac><mi>n</mi><mo>⌋</mo></mrow></mrow></semantics></math></inline-formula>, respectively, where <i>n</i> is the order of the block graph. Finally, we devise a linear time algorithm to calculate the block order sequence.
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spelling doaj.art-f6fd56e00ab1497c92f49eda9b9d2f9c2023-11-30T20:50:05ZengMDPI AGAxioms2075-16802022-03-0111311410.3390/axioms11030114The Average Eccentricity of Block Graphs: A Block Order Sequence PerspectiveXingfu Li0Guihai Yu1Kinkar Chandra Das2College of Big Data Statistics, Guizhou University of Finance and Economics, Guiyang 550025, ChinaCollege of Big Data Statistics, Guizhou University of Finance and Economics, Guiyang 550025, ChinaDepartment of Mathematics, Sungkyunkwan University, Suwon 16419, KoreaA graph is a <i>block graph</i> if its blocks are all cliques. In this paper, we study the average eccentricity of block graphs from the perspective of <i>block order sequences</i>. An equivalence relation is established under the block order sequence and used to prove the lower and upper bounds of the eccentricity on block graphs. The result is that the lower and upper bounds of the average eccentricity on block graphs are 1 and <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mfrac><mn>1</mn><mi>n</mi></mfrac><mrow><mo>⌊</mo><mfrac><mn>3</mn><mn>4</mn></mfrac><msup><mi>n</mi><mn>2</mn></msup><mo>−</mo><mfrac><mn>1</mn><mn>2</mn></mfrac><mi>n</mi><mo>⌋</mo></mrow></mrow></semantics></math></inline-formula>, respectively, where <i>n</i> is the order of the block graph. Finally, we devise a linear time algorithm to calculate the block order sequence.https://www.mdpi.com/2075-1680/11/3/114block order sequenceblock graphsaverage eccentricity
spellingShingle Xingfu Li
Guihai Yu
Kinkar Chandra Das
The Average Eccentricity of Block Graphs: A Block Order Sequence Perspective
Axioms
block order sequence
block graphs
average eccentricity
title The Average Eccentricity of Block Graphs: A Block Order Sequence Perspective
title_full The Average Eccentricity of Block Graphs: A Block Order Sequence Perspective
title_fullStr The Average Eccentricity of Block Graphs: A Block Order Sequence Perspective
title_full_unstemmed The Average Eccentricity of Block Graphs: A Block Order Sequence Perspective
title_short The Average Eccentricity of Block Graphs: A Block Order Sequence Perspective
title_sort average eccentricity of block graphs a block order sequence perspective
topic block order sequence
block graphs
average eccentricity
url https://www.mdpi.com/2075-1680/11/3/114
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