Ars Combinatoria

ISSN 0381-7032 (print), 2817-5204 (online)

Ars Combinatoria is the oldest Canadian journal of combinatorics, established in 1976, dedicated to advancing combinatorial mathematics through the publication of high-quality, peer-reviewed research papers. Over the decades, it has built a strong international reputation and continues to serve as a leading platform for significant contributions to the field.
Open Access:  The journal follows the Diamond Open Access model—completely free for both authors and readers, with no article processing charges (APCs)
Publication Frequency: From 2024 onward, Ars Combinatoria publishes four issues annually—in March, June, September, and December.
Scope: Publishes research in all areas of combinatorics, including graph theory, design theory, enumeration, algebraic combinatorics, combinatorial optimization and related fields.
Indexing & Abstracting:  Indexed in MathSciNet, Zentralblatt MATH, and EBSCO, ensuring wide visibility and scholarly reach.
Rapid Publication: Submissions are processed efficiently, with accepted papers published promptly in the next available issue.
Print & Online Editions: Issues are available in both print and online formats to serve a broad readership.

Marta Na Chen1, Wenchang Chu2
1School of Mathematics and Statistics, Zhoukou Normal University Zhoukou (Henan), China
2Via Dalmazio Birago 9E, Lecce 73100, Italy
Abstract:

By employing Kummer and Thomae transformations, we examine four classes of nonterminating \(_3F_2\)(1)-series with five integer parameters. Several new summation formulae are established in closed form.

Somnath Bera1, Kinkar Chandra Das2
1School of Automation, Huazhong University of Science and Technology, Wuhan 430074, China.
2Department of Mathematics, Sungkyunkwan University, Suwon 16419, Republic of Korea.
Abstract:

Let \(G=(V,\,E)\) be a simple graph with vertex set \(V(G)\) and edge set \(E(G)\). The Lanzhou index of a graph \(G\) is defined by \(Lz(G)=\sum\limits_{u \in V(G)} d_u^2\overline{d}_u\), where \(d_u\) (\(\overline{d}_u \) resp.) denotes the degree of the vertex \(u\) in \(G\) (\(\overline{G}\), the complement graph of \(G\) resp.). It has predictive powers to provide insights of chemical relevant properties of chemical graph structures. In this paper we discuss some properties of Lanzhou index. Several inequalities having lower and upper bound for the Lanzhou index in terms of first, second and third Zagreb indices, radius of graph, eccentric connectivity index, Schultz index, inverse sum indeg index and symmetric division deg index, are discussed. At the end the Lanzhou index of corona and join of graphs have been derived.

Christian Rubio-Montiel1
1División de Matemáticas e Ingeniería, FES Acatlán, Universidad Nacional Autónoma de México, 53150, Naucalpan, Mexico.
Abstract:

We define an extremal \((r|\chi)\)-graph as an \(r\)-regular graph with chromatic number \(\chi\) of minimum order. We show that the Turán graphs \(T_{ak,k}\), the antihole graphs and the graphs \(K_k\times K_2\) are extremal in this sense. We also study extremal Cayley \((r|\chi)\)-graphs and we exhibit several \((r|\chi)\)-graph constructions arising from Turán graphs.

Jishnu Sen1, Srinivasa Rao Kola1
1Department of Mathematical and Computational Sciences National Institute of Technology Karnataka, Surathkal Mangalore – 575025, India.
Abstract:

A dominating broadcast of a graph \(G\) is a function \(f : V(G) \rightarrow \lbrace 0, 1, 2, \dots ,\text{diam}(G)\rbrace\) such that \(f(v) \leqslant e(v)\) for all \(v \in V(G)\), where \(e(v)\) is the eccentricity of \(v\), and for every vertex \(u \in V(G)\), there exists a vertex \(v\) with \(f(v) > 0\) and \(\text{d}(u,v) \leqslant f(v)\). The cost of \(f\) is \(\sum_{v \in V(G)} f(v)\). The minimum of costs over all the dominating broadcasts of \(G\) is called the broadcast domination number \(\gamma_{b}(G)\) of \(G\). A graph $G$ is said to be radial if \(\gamma_{b}(G)=\text{rad}(G)\). In this article, we give tight upper and lower bounds for the broadcast domination number of the line graph \(L(G)\) of \(G\), in terms of \(\gamma_{b}(G)\), and improve the upper bound of the same for the line graphs of trees. We present a necessary and sufficient condition for radial line graphs of central trees, and exhibit constructions of infinitely many central trees \(T\) for which \(L(T)\) is radial. We give a characterization for radial line graphs of trees, and show that the line graphs of the \(i\)-subdivision graph of \(K_{1,n}\) and a subclass of caterpillars are radial. Also, we show that \(\gamma_{b}(L(C))=\gamma(L(C))\) for any caterpillar \(C\).

P. Titus1, S. Antin Mary2
1Department of Mathematics, University College of Engineering Nagercoil, Anna University, Tirunelveli Region.
2Department of Mathematics,Holy Cross College (Autonomous), Nagercoil, India.
Abstract:

In this paper we introduce the concept of independent fixed connected geodetic number and investigate its behaviours on some standard graphs. Lower and upper bounds are found for the above number and we characterize the suitable graphs achieving these bounds. We also define two new parameters connected geo-independent number and upper connected geo-independent number of a graph. Few characterization and realization results are formulated for the new parameters. Finally an open problem is posed.

Sunny Kumar Sharma1, Vijay Kumar Bhat2
1Department of Mathematics, Manipal Institute of Technology Bengaluru, Manipal Academy of Higher Education, Manipal, Karnataka, India.
2School of Mathematics, Shri Mata Vaishno Devi University, Katra-182320, India.
Abstract:

Let \(E(H)\) and \(V(H)\) denote the edge set and the vertex set of the simple connected graph \(H\), respectively. The mixed metric dimension of the graph \(H\) is the graph invariant, which is the mixture of two important graph parameters, the edge metric dimension and the metric dimension. In this article, we compute the mixed metric dimension for the two families of the plane graphs viz., the Web graph \(\mathbb{W}_{n}\) and the Prism allied graph \(\mathbb{D}_{n}^{t}\). We show that the mixed metric dimension is non-constant unbounded for these two families of the plane graph. Moreover, for the Web graph \(\mathbb{W}_{n}\) and the Prism allied graph \(\mathbb{D}_{n}^{t}\), we unveil that the mixed metric basis set \(M_{G}^{m}\) is independent.

A. Lourdusamy1, F. Joy Beaula2, F. Patrick1
1Department of Mathematics, St. Xavier’s College (Autonomous), Palayamkottai-627002, India.
2Center: PG and Research Department of Mathematics, St. Xavier’s College (Autonomous), Palayamkottai-627002, Manonmaniam Sundaranar University, Abisekapatti-627012, Tamilnadu, India.
Abstract:

Consider a total labeling \(\xi\) of a graph \(G\). For every two different edges \(e\) and \(f\) of \(G\), let \(wt(e) \neq wt(f)\) where weight of \(e = xy\) is defined as \(wt(e)=|\xi(e) – \xi(x) – \xi(y)|\). Then \(\xi\) is called edge irregular total absolute difference \(k\)-labeling of \(G\). Let \(k\) be the minimum integer for which there is a graph \(G\) with edge irregular total absolute difference labeling. This \(k\) is called the total absolute difference edge irregularity strength of the graph \(G\), denoted \(tades(G)\). We compute \(tades\) of \(SC_{n}\), disjoint union of grid and zigzag graph.

Wei Ge1, Jun Yue2
1Shandong University of Engineering and Vocational Technology, Ji’nan, Shandong, China.
2School of Mathematics Science, Tiangong University, Tianjin, China.
Abstract:

A total dominator coloring of \(G\) without isolated vertex is a proper coloring of the vertices of \(G\) in which each vertex of \(G\) is adjacent to every vertex of some color class. The total dominator chromatic number \(\chi^t_d(G)\) of \(G\) is the minimum number of colors among all total dominator coloring of \(G\). In this paper, we will give the polynomial time algorithms to computing the total dominator coloring number for \(P_4\)-reducible and \(P_4\)-tidy graphs.

Solomon Stalin Kumar1
1Department of Mathematics, The American College, Madurai – 625 002, Tamilnadu, India.
Abstract:

An \(H\)-(a,d)-antimagic labeling in a \(H\)-decomposable graph \(G\) is a bijection \(f: V(G)\cup E(G)\rightarrow {\{1,2,…,p+q\}}\) such that \(\sum f(H_1),\sum f(H_2),\cdots, \sum f(H_h)\) forms an arithmetic progression with difference \(d\) and first element \(a\). \(f\) is said to be \(H\)-\(V\)-super-\((a,d)\)-antimagic if \(f(V(G))={\{1,2,…,p\}}\). Suppose that \(V(G)=U(G) \cup W(G)\) with \(|U(G)|=m\) and \(|W(G)|=n\). Then \(f\) is said to be \(H\)-\(V\)-super-strong-\((a,d)\)-antimagic labeling if \(f(U(G))={\{1,2,…,m\}}\) and \(f(W(G))={\{m+1,m+2,…,(m+n=p)\}}\). A graph that admits a \(H\)-\(V\)-super-strong-\((a,d)\)-antimagic labeling is called a \(H\)-\(V\)-super-strong-\((a,d)\)-antimagic decomposable graph. In this paper, we prove that complete bipartite graphs \(K_{m,n}\) are \(H\)-\(V\)-super-strong-\((a,d)\)-antimagic decomposable with both \(m\) and \(n\) are even.

Stella Maragatham R1, Subramanian A 2
1Department of Mathematics, Queen Mary’s College, Chennai-600 004, Tamil Nadu, India.
2Department of Mathematics, Presidency College, Chennai-600005, Tamil Nadu, India.
Abstract:

A Grundy \(k\)-coloring of a graph \(G\) is a proper \(k\)-coloring of vertices in \(G\) using colors \(\{1, 2, \cdots, k\}\) such that for any two colors \(x\) and \(y\), \(x<y\), any vertex colored \(y\) is adjacent to some vertex colored \(x\). The First-Fit or Grundy chromatic number (or simply Grundy number) of a graph \(G\), denoted by \(\Gamma \left(G\right)\), is the largest integer \(k\), such that there exists a Grundy \(k\)-coloring for \(G\). It can be easily seen that \(\Gamma \left(G\right)\) equals to the maximum number of colors used by the greedy (or First-Fit) coloring of \(G\). In this paper, we obtain the Grundy chromatic number of Cartesian Product of path graph, complete graph, cycle graph, complete graph, wheel graph and star graph.