{"title":"Unique Response Roman Domination Versus 2-Packing Differential in Complementary Prisms","authors":"Z. N. Berberler, M. Çerezci","doi":"10.1134/s0001434624050237","DOIUrl":null,"url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p> Let <span>\\(G = (V,E)\\)</span> be a graph of order <span>\\(n\\)</span>. For <span>\\(S \\subseteq V(G)\\)</span>, the set <span>\\(N_e(S)\\)</span> is defined as the external neighborhood of <span>\\(S\\)</span> such that all vertices in <span>\\(V(G)\\backslash S\\)</span> have at least one neighbor in <span>\\(S\\)</span>. The differential of <span>\\(S\\)</span> is defined to be <span>\\(\\partial(S)=|N_e(S)|-|S|\\)</span>, and the 2-packing differential of a graph is defined as </p><span>$$\\partial_{2p}(G) =\\max\\{\\partial(S)\\colon S \\subseteq V(G) \\text{ is a 2-packing}\\}.$$</span><p> A function <span>\\(f\\colon V(G) \\to \\{0,1,2\\}\\)</span> with the sets <span>\\(V_0,V_1,V_2\\)</span>, where </p><span>$$V_i =\\{v\\in V(G)\\colon f(v) = i\\},\\qquad i \\in \\{0,1,2\\},$$</span><p> is a unique response Roman dominating function if <span>\\(x \\in V_0 \\)</span> implies that <span>\\(| N( x ) \\cap V_2 | = 1\\)</span> and <span>\\(x \\in V_1 \\cup V_2 \\)</span> implies that <span>\\(N( x ) \\cap V_2 = \\emptyset\\)</span>. The unique response Roman domination number of <span>\\(G\\)</span>, denoted by <span>\\(\\mu_R(G)\\)</span>, is the minimum weight among all unique response Roman dominating functions on <span>\\(G\\)</span>. Let <span>\\(\\bar{G}\\)</span> be the complement of a graph <span>\\(G\\)</span>. The complementary prism <span>\\(G\\bar {G}\\)</span> of <span>\\(G\\)</span> is the graph formed from the disjoint union of <span>\\(G\\)</span> and <span>\\(\\bar {G}\\)</span> by adding the edges of a perfect matching between the respective vertices of <span>\\(G\\)</span> and <span>\\(\\bar {G}\\)</span>. The present paper deals with the computation of the 2-packing differential and the unique response Roman domination of the complementary prisms <span>\\(G\\bar {G}\\)</span> by the use of a proven Gallai-type theorem. Particular attention is given to the complementary prims of special types of graphs. Furthermore, the graphs <span>\\(G\\)</span> such that <span>\\(\\partial_{2p} ( G\\bar G)\\)</span> and <span>\\(\\mu _R(G\\bar G)\\)</span> are small are characterized. </p>","PeriodicalId":0,"journal":{"name":"","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"","FirstCategoryId":"100","ListUrlMain":"https://doi.org/10.1134/s0001434624050237","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 0
Abstract
Let \(G = (V,E)\) be a graph of order \(n\). For \(S \subseteq V(G)\), the set \(N_e(S)\) is defined as the external neighborhood of \(S\) such that all vertices in \(V(G)\backslash S\) have at least one neighbor in \(S\). The differential of \(S\) is defined to be \(\partial(S)=|N_e(S)|-|S|\), and the 2-packing differential of a graph is defined as
$$\partial_{2p}(G) =\max\{\partial(S)\colon S \subseteq V(G) \text{ is a 2-packing}\}.$$
A function \(f\colon V(G) \to \{0,1,2\}\) with the sets \(V_0,V_1,V_2\), where
$$V_i =\{v\in V(G)\colon f(v) = i\},\qquad i \in \{0,1,2\},$$
is a unique response Roman dominating function if \(x \in V_0 \) implies that \(| N( x ) \cap V_2 | = 1\) and \(x \in V_1 \cup V_2 \) implies that \(N( x ) \cap V_2 = \emptyset\). The unique response Roman domination number of \(G\), denoted by \(\mu_R(G)\), is the minimum weight among all unique response Roman dominating functions on \(G\). Let \(\bar{G}\) be the complement of a graph \(G\). The complementary prism \(G\bar {G}\) of \(G\) is the graph formed from the disjoint union of \(G\) and \(\bar {G}\) by adding the edges of a perfect matching between the respective vertices of \(G\) and \(\bar {G}\). The present paper deals with the computation of the 2-packing differential and the unique response Roman domination of the complementary prisms \(G\bar {G}\) by the use of a proven Gallai-type theorem. Particular attention is given to the complementary prims of special types of graphs. Furthermore, the graphs \(G\) such that \(\partial_{2p} ( G\bar G)\) and \(\mu _R(G\bar G)\) are small are characterized.