{"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":18294,"journal":{"name":"Mathematical Notes","volume":"48 1","pages":""},"PeriodicalIF":0.6000,"publicationDate":"2024-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Mathematical Notes","FirstCategoryId":"100","ListUrlMain":"https://doi.org/10.1134/s0001434624050237","RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"MATHEMATICS","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.
期刊介绍:
Mathematical Notes is a journal that publishes research papers and review articles in modern algebra, geometry and number theory, functional analysis, logic, set and measure theory, topology, probability and stochastics, differential and noncommutative geometry, operator and group theory, asymptotic and approximation methods, mathematical finance, linear and nonlinear equations, ergodic and spectral theory, operator algebras, and other related theoretical fields. It also presents rigorous results in mathematical physics.