On Hop Roman Domination in Trees
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Abstract:
Let $G=(V,E)$ be a graph. A subset $Ssubset V$ is a hop dominating setif every vertex outside $S$ is at distance two from a vertex of$S$. A hop dominating set $S$ which induces a connected subgraph is called a connected hop dominating set of $G$. Theconnected hop domination number of $G$, $ gamma_{ch}(G)$, is the minimum cardinality of a connected hopdominating set of $G$. A hopRoman dominating function (HRDF) of a graph $G$ is a function $f: V(G)longrightarrow {0, 1, 2} $ having the property thatfor every vertex $ v in V $ with $ f(v) = 0 $ there is avertex $ u $ with $ f(u)=2 $ and $ d(u,v)=2 $.The weight ofan HRDF $ f $ is the sum $f(V) = sum_{vin V} f(v) $. Theminimum weight of an HRDF on $ G $ is called the hop Romandomination number of $ G $ and is denoted by $ gamma_{hR}(G)$. We give an algorithmthat decides whether $gamma_{hR}(T)=2gamma_{ch}(T)$ for a giventree $T$.{bf Keywords:} hop dominating set, connected hop dominating set, hop Roman dominatingfunction.
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Journal title
volume 4 issue 2
pages 201- 208
publication date 2019-12-01
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