{"title":"半总支配数为其阶数一半的图","authors":"JIE CHEN, SHOU-JUN XU","doi":"10.1017/s0004972724000509","DOIUrl":null,"url":null,"abstract":"<p>In an isolate-free graph <span>G</span>, a subset <span>S</span> of vertices is a <span>semitotal dominating set</span> of <span>G</span> if it is a dominating set of <span>G</span> and every vertex in <span>S</span> is within distance 2 of another vertex of <span>S</span>. The <span>semitotal domination number</span> of <span>G</span>, denoted by <span><span><img data-mimesubtype=\"png\" data-type=\"\" src=\"https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20240912125800045-0875:S0004972724000509:S0004972724000509_inline1.png\"><span data-mathjax-type=\"texmath\"><span>$\\gamma _{t2}(G)$</span></span></img></span></span>, is the minimum cardinality of a semitotal dominating set in <span>G</span>. Goddard, Henning and McPillan [‘Semitotal domination in graphs’, <span>Utilitas Math.</span> <span>94</span> (2014), 67–81] characterised the trees and graphs of minimum degree 2 with semitotal domination number half their order. In this paper, we characterise all graphs whose semitotal domination number is half their order.</p>","PeriodicalId":0,"journal":{"name":"","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"GRAPHS WITH SEMITOTAL DOMINATION NUMBER HALF THEIR ORDER\",\"authors\":\"JIE CHEN, SHOU-JUN XU\",\"doi\":\"10.1017/s0004972724000509\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p>In an isolate-free graph <span>G</span>, a subset <span>S</span> of vertices is a <span>semitotal dominating set</span> of <span>G</span> if it is a dominating set of <span>G</span> and every vertex in <span>S</span> is within distance 2 of another vertex of <span>S</span>. The <span>semitotal domination number</span> of <span>G</span>, denoted by <span><span><img data-mimesubtype=\\\"png\\\" data-type=\\\"\\\" src=\\\"https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20240912125800045-0875:S0004972724000509:S0004972724000509_inline1.png\\\"><span data-mathjax-type=\\\"texmath\\\"><span>$\\\\gamma _{t2}(G)$</span></span></img></span></span>, is the minimum cardinality of a semitotal dominating set in <span>G</span>. Goddard, Henning and McPillan [‘Semitotal domination in graphs’, <span>Utilitas Math.</span> <span>94</span> (2014), 67–81] characterised the trees and graphs of minimum degree 2 with semitotal domination number half their order. In this paper, we characterise all graphs whose semitotal domination number is half their order.</p>\",\"PeriodicalId\":0,\"journal\":{\"name\":\"\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":0.0,\"publicationDate\":\"2024-09-13\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"\",\"FirstCategoryId\":\"100\",\"ListUrlMain\":\"https://doi.org/10.1017/s0004972724000509\",\"RegionNum\":0,\"RegionCategory\":null,\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"\",\"JCRName\":\"\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"","FirstCategoryId":"100","ListUrlMain":"https://doi.org/10.1017/s0004972724000509","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 0
摘要
在无孤立图 G 中,如果顶点子集 S 是 G 的支配集,且 S 中的每个顶点与 S 中另一个顶点的距离都在 2 以内,则该顶点子集 S 是 G 的半总支配集。G 的半总支配数用 $\gamma _{t2}(G)$ 表示,是 G 中半总支配集的最小心性。Goddard、Henning 和 McPillan ['图中的半总支配数',Utilitas Math.在本文中,我们将描述所有半总支配数为其阶数一半的图的特征。
GRAPHS WITH SEMITOTAL DOMINATION NUMBER HALF THEIR ORDER
In an isolate-free graph G, a subset S of vertices is a semitotal dominating set of G if it is a dominating set of G and every vertex in S is within distance 2 of another vertex of S. The semitotal domination number of G, denoted by $\gamma _{t2}(G)$, is the minimum cardinality of a semitotal dominating set in G. Goddard, Henning and McPillan [‘Semitotal domination in graphs’, Utilitas Math.94 (2014), 67–81] characterised the trees and graphs of minimum degree 2 with semitotal domination number half their order. In this paper, we characterise all graphs whose semitotal domination number is half their order.