arXiv subjects

Azam Sadat Emadi

Publications and source records attributed to Azam Sadat Emadi.

5 recordsLinked to original sources

arXiv2025

Edge Coalitions in Graphs

Coalition concepts have been extensively studied in domination theory for vertex sets, whereas their edge counterparts have remained largely unexplored. Motivated by this, we introduce the notions of edge coalition, edge coalition partition, edge coalition number, and edge coalition graph. We prove that every graph admits an edge coalition partition and establish fundamental properties of these concepts. We derive sharp bounds for the edge coalition number, characterize graphs attaining its extremal values, and determine this parameter for several important graph classes, including complete graphs, complete bipartite graphs, paths, cycles, stars, trees, and unicyclic graphs. We further introduce the edge coalition graph associated with an edge coalition partition and investigate its structural properties. In particular, we characterize the edge coalition graphs of several graph classes and identify all self-edge coalition graphs. These results extend coalition theory from vertices to edges and provide a foundation for further research on edge coalition structures.

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arXiv2024

Further Results on the Majority Roman Domination in graphs

Let $G=(V,E)$ be a simple graph of order $n$. A Majority Roman Dominating Function (MRDF) on a graph G is a function $f: V\rightarrow\{-1, +1, 2\}$ if the sum of its function values over at least half the closed neighborhoods is at least one , this is , for at least half of the vertices $v\in V$, $f(N[v])\geq 1$. Moreover, every vertex u with $f(u)=-1$ is adjacent to at least one vertex $w$ with $f(w)=2$. The Majority Roman Domination number of a graph $G$, denoted by $\gamma_{MR}(G)$ , is the minimum value of $\sum_{v\in{V(G)}}f(v)$ over all Majority Roman Dominating Function $f$ of $G$. In this paper we study properties of the Majority Roman Domination in graphs and obtain lower and upper bounds the Majority Roman Domination number of some graphs.

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arXiv2023

Edge coalitions in graphs

An edge coalition in a graph $G=(V,E)$ consists of two disjoint sets of edges $E_1$ and $E_2$, neither of which is an edge dominating set but whose union $E_1\cup E_2$ is an edge dominating set. An edge coalition partition in a graph $G$ of order $n=|V|$ and size $m$ is an edge partition $\pi=\{E_1,\cdots,E_k\}$ so that every set $E_i$ of $\pi$ either is a singleton edge dominating set, or is not an edge dominating set but forms an edge coalition with another set $E_j$ which is not an edge dominating set. In this paper we introduce the concept of edge coalition and show that there exists edge coalition for some graphs and trees. The graphs $G$ with small and size number of edge coalition are characterized. Finally, coalition graphs of special graphs are studied.

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arXiv2022

Majority dominator colorings of graphs

Let $G$ be a simple graph of order $n$. A majority dominator coloring of a graph $G$ is proper coloring in which each vertex of the graph dominates at least half of one color class. The majority dominator chromatic number $χ_{md}(G)$ is the minimum number of color classes in a majority dominator coloring of $G$. In this paper we study properties of the majority dominator coloring of a graph. We obtain tight upper and lower bounds in terms of chromatic number, dominator chromatic number, maximum degree, domination and independence number. We also study majority dominator coloring number of selected families of graphs.

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arXiv2020

Total vertex product irregularity strength of graphs

Consider a simple graph $G$. We call a labeling $w:E(G)\cup V(G)\rightarrow \{1, 2, \dots, s\}$ (\textit{total vertex}) \textit{product-irregular}, if all product degrees $pd_G(v)$ induced by this labeling are distinct, where $pd_G(v)=w(v)\times\prod_{e\ni v}w(e)$. The strength of $w$ is $s$, the maximum number used to label the members of $E(G)\cup V(G)$. The minimum value of $s$ that allows some irregular labeling is called \textit{the total vertex product irregularity strength} and denoted $tvps(G)$. We provide some general bounds, as well as exact values for chosen families of graphs. Keywords: product-irregular labeling, total vertex product irregularity strength, vertex-distinguishing labeling.

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