Utilitas Algorithmica (UA)

ISSN: xxxx-xxxx (print)

Utilitas Algorithmica (UA) is a premier, open-access international journal dedicated to advancing algorithmic research and its applications. Launched to drive innovation in computer science, UA publishes high-impact theoretical and experimental papers addressing real-world computational challenges. The journal underscores the vital role of efficient algorithm design in navigating the growing complexity of modern applications. Spanning domains such as parallel computing, computational geometry, artificial intelligence, and data structures, UA is a leading venue for groundbreaking algorithmic studies.

K. Kavitha 1, N.G. David1
1Department of Mathematics, Madras Christian College, Chennai – 600 059
Abstract:

ll graphs considered in our study are simple, finite and undirected. A graph is equitable total domination edge addition critical (stable) if the addition of any arbitrary edge changes (does not change) the equitable total domination number. In this paper, we introduce the following new parameters: equitable independent dom- ination number, equitable total domination number and equitable connected domination number and study their stability upon edge addition, on special families of graphs namely cycles, paths and com- plete bipartite graphs. Also the relation among the above parameters is established.

Sharmila Mary Arul1, P. Sivagami1
1Department of Mathematics, Jeppiaar Engineering College, Chennai 600119, India
Abstract:

The \(k\)-rainbow domination is a variant of the classical domination problem in graphs and is defined as follows: Given an undirected graph \(G = (V, E)\) and a set of \(k\) colors numbered \(1, 2, \dots, k\), we assign an arbitrary subset of these colors to each vertex of \(G\). If a vertex is assigned the empty set, then the union of color sets of its neighbors must be \(k\) colors. This assignment is called the \(k\)-rainbow dominating function of \(G\). The minimum sum of numbers of assigned colors over all vertices of \(G\), is called the \(k\)-rainbow domination number of \(G\). In this paper, we present some bounds on the \(3\)-rainbow domination number of circulant networks and grid networks.

Jasintha Quadras1, Vasanthika S2
1Department of Mathematics, Stella Maris College, Chennai 600 034, India
2School of Advanced Sciences, VIT University, Chennai 600 127, India
Abstract:

A linear layout, or simply a layout, of an undirected graph \( G = (V, E) \) with \( n = |V| \) vertices is a bijective function \( \phi: V \to \{1, 2, \dots, n\} \). A \( k \)-coloring of a graph \( G = (V, E) \) is a mapping \( \kappa: V \to \{c_1, c_2, \dots, c_k\} \) such that no two adjacent vertices have the same color. A graph with a \( k \)-coloring is called a \( k \)-colored graph.

A colored layout of a \( k \)-colored graph \( (G, \kappa) \) is a layout \( \phi \) of \( G \) such that for any \( u, x, v \in V \), if \( (u, v) \in E \) and \( \phi(u) < \phi(x) < \phi(v) \), then \( \kappa(u) \neq \kappa(x) \). Given a \( k \)-colored graph \( (G, \kappa) \), the problem of deciding whether there is a colored layout \( \phi \) of \( (G, \kappa) \) is NP-complete. In this paper, we introduce the concept of chromatic layout of \( G \) and determine the chromatic layout number for paths and cycles.

V. Annamma1
1Department of Mathematics, L. N. Government College, Ponneri, India
Abstract:

Let \( G(V, E) \) be a simple graph. For a labeling \( \partial: V \cup E \to \{1, 2, 3, \dots, k\} \), the weight of a vertex \( x \) is defined as

\[
wt(x) = \partial(x) + \sum_{xy \in E} \partial(xy).
\]

The labeling \( \partial \) is called a vertex irregular total \( k \)-labeling if for every pair of distinct vertices \( x \) and \( y \), \( wt(x) \neq wt(y) \). The minimum \( k \) for which the graph \( G \) has a vertex irregular total \( k \)-labeling is called the total vertex irregularity strength of \( G \) and is denoted by \( tvs(G) \). In this paper, we obtain a bound for the total vertex irregularity strength of honeycomb and honeycomb derived networks.

Jasintha Quadras1, S. Sarah Surya1
1Stella Maris College, Chennai 600 086, India
Abstract:

Graph embedding is an important technique used in the study of computational capabilities of processor interconnection networks and task distribution. In this paper, we present an algorithm for embedding the Hypercubes into Banana Trees and Extended Banana Trees and prove its correctness using the Congestion lemma and Partition lemma.

S. Little Joice1
1Department of Mathematics, Loyola College, Chennai 600 034, India.
Abstract:

A kernel in a directed graph \(D(V, E)\) is a set \(S\) of vertices of \(D\) such that no two vertices in \(S\) are adjacent and for every vertex \(u\) in \(V \setminus S\), there is a vertex \(v\) in \(S\) such that \((u, v)\) is an arc of \(D\). The problem of existence of a kernel is NP-complete for a general digraph. In this paper, we introduce the acyclic kernel problem of an undirected graph \(G\) and solve it in polynomial time for uniform theta graphs and even quasi-uniform theta graphs.

Jasintha Quadra 1, S. Teresa Arockiamary1
1Department of Mathematics, Stella Maris College, Chennai, India.
Abstract:

Given a graph \( G = (V, E) \), a labeling \( \partial: V \cup E \to \{1, 2, \dots, k\} \) is called an edge irregular total \( k \)-labeling if for every pair of distinct edges \( uv \) and \( xy \), \( \partial(u) + \partial(uv) + \partial(v) \neq \partial(x) + \partial(xy) + \partial(y) \). The minimum \( k \) for which \( G \) has an edge irregular total \( k \)-labeling is called the total edge irregularity strength of \( G \). In this paper, we examine the hexagonal network, which is a well-known interconnection network, and obtain its total edge irregularity strength.

N. Parthiban1, R. Sundara Rajan1, Indra Rajasingh2
1School of Computing Sciences and Enginnering, VIT, Chennai, Tamilnadu, India.
2School of Advanced Sciences, VIT, Chennai, Tamilnadu, India.
Abstract:

Graph embedding problems have gained importance in the field of interconnection networks for parallel computer architectures. In this paper, we prove that grid and cylinder are the subgraphs of certain circulant networks. Further, we present an algorithm to embed tori into certain circulant networks with dilation\(2\) and vice-versa.

A. Shanthakumari1
1Department of Mathematics M.O.P. Vaishnav College for Women (Autonomous), Chennai, India
Abstract:

Broadcasting is a fundamental information dissemination problem in a connected graph, in which one vertex called the originator disseminates one or more messages to all other vertices in the graph. \(A\)-broadcasting is a variant of broadcasting in which an informed vertex can disseminate a message to at most \(k\) uninformed vertices in one unit of time. In general, solving the broadcast problem in an arbitrary graph is NP-complete. In this paper, we obtain the \(k\)-broadcast time of the Sierpiński gasket graphs for all \(k \geq 1\).

Charles Robert Kenneth1
1Department of Mathematics, Loyola College, Chennai, India
Abstract:

Let \( G = (V, E) \) be a graph with vertex set \( V \) and edge set \( E \). Let \( \text{diam}(G) \) denote the diameter of \( G \) and \( d(u, v) \) denote the distance between the vertices \( u \) and \( v \) in \( G \). An antipodal labeling of \( G \) with diameter \( d \) is a function \( f \) that assigns to each vertex \( u \), a positive integer \( f(u) \), such that \( d(u, v) + |f(u) – f(v)| \geq d \), for all \( u, v \in V \). The span of an antipodal labeling \( f \) is \( \max \{|f(u) – f(v)| : u, v \in V(G)\} \). The antipodal number for \( G \), denoted by \( \text{an}(G) \), is the minimum span of all antipodal labelings of \( G \). Determining the antipodal number of a graph \( G \) is an NP-complete problem. In this paper, we determine the antipodal number of certain graphs.

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