Characterization of Some Claw-Free Graphs in Co-Secure Domination Number

For a vertex subset <i>S</i> of a graph <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>G</mi><mo>,</mo></mrow></semantics></math></inline-formu...

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Main Authors: Yuexin Zhang, Jiayuan Zhang, Siwen Jing, Xiaodong Chen, Liming Xiong
Format: Article
Language:English
Published: MDPI AG 2025-07-01
Series:Mathematics
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Online Access:https://www.mdpi.com/2227-7390/13/15/2426
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author Yuexin Zhang
Jiayuan Zhang
Siwen Jing
Xiaodong Chen
Liming Xiong
author_facet Yuexin Zhang
Jiayuan Zhang
Siwen Jing
Xiaodong Chen
Liming Xiong
author_sort Yuexin Zhang
collection DOAJ
description For a vertex subset <i>S</i> of a graph <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>G</mi><mo>,</mo></mrow></semantics></math></inline-formula> if each vertex of <i>G</i> is either in <i>S</i> or adjacent to some vertex in <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>S</mi><mo>,</mo></mrow></semantics></math></inline-formula> then <i>S</i> is a dominating set of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>G</mi><mo>.</mo></mrow></semantics></math></inline-formula> Let <i>S</i> be a dominating set of a graph <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>G</mi><mo>.</mo></mrow></semantics></math></inline-formula> If each vertex <i>v</i> not in <i>S</i> has a neighbor <i>u</i> in <i>S</i> such that <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mo>(</mo><mi>S</mi><mo>\</mo><mo>{</mo><mi>u</mi><mo>}</mo><mo>)</mo><mo>∪</mo><mo>{</mo><mi>v</mi><mo>}</mo></mrow></semantics></math></inline-formula> is also a dominating set of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>G</mi><mo>,</mo></mrow></semantics></math></inline-formula> then <i>S</i> is a secure dominating set of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>G</mi><mo>.</mo></mrow></semantics></math></inline-formula> If each vertex <i>u</i> in <i>S</i> has a neighbor <i>v</i> not in <i>S</i> such that <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mo>(</mo><mi>S</mi><mo>\</mo><mo>{</mo><mi>u</mi><mo>}</mo><mo>)</mo><mo>∪</mo><mo>{</mo><mi>v</mi><mo>}</mo></mrow></semantics></math></inline-formula> is also a dominating set of <i>G</i>, then <i>S</i> is a co-secure dominating set of <i>G</i>. The minimum cardinality of a secure (resp. co-secure) dominating set of <i>G</i> is the secure (resp. co-secure) domination number of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>G</mi><mo>.</mo></mrow></semantics></math></inline-formula> Arumugam et al. proposed the questions to characterize a graph <i>G</i> such that the co-secure domination number of <i>G</i> equals the independence number and the secure domination number of <i>G</i>, respectively. Inspired by those questions, in this paper, we obtain two classes of claw-free graphs such that the co-secure domination number equal the independence number and the secure domination number. Our results provide some theoretical basis of claw-free graphs for networks.
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spelling doaj-art-e0a3820c88864624aa88ce93eda88c982025-08-20T03:36:34ZengMDPI AGMathematics2227-73902025-07-011315242610.3390/math13152426Characterization of Some Claw-Free Graphs in Co-Secure Domination NumberYuexin Zhang0Jiayuan Zhang1Siwen Jing2Xiaodong Chen3Liming Xiong4School of Mathematics, Liaoning Normal University, Dalian 116029, ChinaSchool of Mathematics, Liaoning Normal University, Dalian 116029, ChinaSchool of Mathematics, Liaoning Normal University, Dalian 116029, ChinaSchool of Mathematics, Liaoning Normal University, Dalian 116029, ChinaSchool of Mathematics and Statistics, Beijing Key Laboratory on MCAACI, Beijing Institute of Technology, Beijing 100081, ChinaFor a vertex subset <i>S</i> of a graph <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>G</mi><mo>,</mo></mrow></semantics></math></inline-formula> if each vertex of <i>G</i> is either in <i>S</i> or adjacent to some vertex in <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>S</mi><mo>,</mo></mrow></semantics></math></inline-formula> then <i>S</i> is a dominating set of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>G</mi><mo>.</mo></mrow></semantics></math></inline-formula> Let <i>S</i> be a dominating set of a graph <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>G</mi><mo>.</mo></mrow></semantics></math></inline-formula> If each vertex <i>v</i> not in <i>S</i> has a neighbor <i>u</i> in <i>S</i> such that <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mo>(</mo><mi>S</mi><mo>\</mo><mo>{</mo><mi>u</mi><mo>}</mo><mo>)</mo><mo>∪</mo><mo>{</mo><mi>v</mi><mo>}</mo></mrow></semantics></math></inline-formula> is also a dominating set of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>G</mi><mo>,</mo></mrow></semantics></math></inline-formula> then <i>S</i> is a secure dominating set of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>G</mi><mo>.</mo></mrow></semantics></math></inline-formula> If each vertex <i>u</i> in <i>S</i> has a neighbor <i>v</i> not in <i>S</i> such that <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mo>(</mo><mi>S</mi><mo>\</mo><mo>{</mo><mi>u</mi><mo>}</mo><mo>)</mo><mo>∪</mo><mo>{</mo><mi>v</mi><mo>}</mo></mrow></semantics></math></inline-formula> is also a dominating set of <i>G</i>, then <i>S</i> is a co-secure dominating set of <i>G</i>. The minimum cardinality of a secure (resp. co-secure) dominating set of <i>G</i> is the secure (resp. co-secure) domination number of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>G</mi><mo>.</mo></mrow></semantics></math></inline-formula> Arumugam et al. proposed the questions to characterize a graph <i>G</i> such that the co-secure domination number of <i>G</i> equals the independence number and the secure domination number of <i>G</i>, respectively. Inspired by those questions, in this paper, we obtain two classes of claw-free graphs such that the co-secure domination number equal the independence number and the secure domination number. Our results provide some theoretical basis of claw-free graphs for networks.https://www.mdpi.com/2227-7390/13/15/2426co-secure dominating setsecure dominating setco-secure domination numbersecure domination number
spellingShingle Yuexin Zhang
Jiayuan Zhang
Siwen Jing
Xiaodong Chen
Liming Xiong
Characterization of Some Claw-Free Graphs in Co-Secure Domination Number
Mathematics
co-secure dominating set
secure dominating set
co-secure domination number
secure domination number
title Characterization of Some Claw-Free Graphs in Co-Secure Domination Number
title_full Characterization of Some Claw-Free Graphs in Co-Secure Domination Number
title_fullStr Characterization of Some Claw-Free Graphs in Co-Secure Domination Number
title_full_unstemmed Characterization of Some Claw-Free Graphs in Co-Secure Domination Number
title_short Characterization of Some Claw-Free Graphs in Co-Secure Domination Number
title_sort characterization of some claw free graphs in co secure domination number
topic co-secure dominating set
secure dominating set
co-secure domination number
secure domination number
url https://www.mdpi.com/2227-7390/13/15/2426
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AT jiayuanzhang characterizationofsomeclawfreegraphsincosecuredominationnumber
AT siwenjing characterizationofsomeclawfreegraphsincosecuredominationnumber
AT xiaodongchen characterizationofsomeclawfreegraphsincosecuredominationnumber
AT limingxiong characterizationofsomeclawfreegraphsincosecuredominationnumber