Abolfazl Poureidi
Abstract
Let $G=(V,E)$ be a graph. A doubleRoman dominating function (DRDF) on $G$ is a function$f:V\to\{0,1,2,3\}$ such that for every vertex $v\in V$if $f(v)=0$, then either there is a vertex $u$ adjacent to $v$ with $f(u)=3$ orthere are vertices $x$ and $y$ adjacent to $v$ with $f(x)=f(y)=2$ and if $f(v)=1$, ...
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Let $G=(V,E)$ be a graph. A doubleRoman dominating function (DRDF) on $G$ is a function$f:V\to\{0,1,2,3\}$ such that for every vertex $v\in V$if $f(v)=0$, then either there is a vertex $u$ adjacent to $v$ with $f(u)=3$ orthere are vertices $x$ and $y$ adjacent to $v$ with $f(x)=f(y)=2$ and if $f(v)=1$, then there is a vertex $u$ adjacent to $v$ with$f(u)\geq2$.A DRDF $f$ on $G$ is a total DRDF (TDRDF) if for any $v\in V$ with $f(v)>0$ there is a vertex $u$ adjacent to $v$ with $f(u)>0$.The weight of $f$ is the sum $f(V)=\sum_{v\in V}f(v)$. The minimum weight of a TDRDF on $G$ is the total double Romandomination number of $G$. In this paper, we give a linear algorithm to compute thetotal double Roman domination number of agiven tree.
M. E. Abdel-Aal; S. Minion; C. Barrientos; D. Williams
Abstract
Mean labelings are a type of additive vertex labeling. This labeling assigns non-negative integers to the vertices of a graph in such a way that all edge-weights are different, where the weight of an edge is defined as the mean of the end-vertex labels rounded up to the nearest integer. In this paper ...
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Mean labelings are a type of additive vertex labeling. This labeling assigns non-negative integers to the vertices of a graph in such a way that all edge-weights are different, where the weight of an edge is defined as the mean of the end-vertex labels rounded up to the nearest integer. In this paper we focus on mean labelings of some graphs that are the result of the corona operation. In particular we prove the existence of mean labelings for graphs of the form G ⊙ mK1 in the cases where G is an even cycle or G is an α-mean graph of odd size and the cardinalities of its stable sets differ by at most one unit. Under these conditions, we prove that G ⊙ P2 and G ⊙ P3 are also mean graphs, and that the class of α-graphs is equivalent to the class of α-mean graphs.
