Journal of Combinatorial Mathematics and Combinatorial Computing

ISSN: 0835-3026 (print) 2817-576X (online)

The Journal of Combinatorial Mathematics and Combinatorial Computing (JCMCC) began its publishing journey in April 1987 and has since become a respected platform for advancing research in combinatorics and its applications.
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, JCMCC publishes four issues annually—in March, June, September, and December.
Scope: JCMCC publishes research in combinatorial mathematics and combinatorial computing, as well as in artificial intelligence and its applications across diverse fields.
Indexing & Abstracting: The journal is indexed in MathSciNet, Zentralblatt MATH, and EBSCO, enhancing its visibility and scholarly impact within the international mathematics community.
Rapid Publication: Manuscripts are reviewed and processed efficiently, with accepted papers scheduled for prompt appearance in the next available issue.
Print & Online Editions: All issues are published in both print and online formats to serve the needs of a wide readership.

G. Sethuraman1, M. Sujasree1
1Department of Mathematics Anna University Chennai – 600 025, INDIA
Abstract:

In 2004, Blinco et al [1] introduced \(\gamma\)-labeling. A function \(h\) defined on the vertex set of a graph \(G\) with \(n\) edges is called a \(\gamma\)-labeling if:

  1. \(h\) is a \(p\)-labeling of \(G\),
  2. \(G\) admits a tripartition \((A, B, C)\) with \(C = \{c\}\) and there exists \(\overline{b} \in B\) such that \((\overline{b}, c)\) is the unique edge with the property that \(h(c) – h(\overline{b}) = n\),
  3. for every edge \(\{a, v\} \in E(G)\) with \(a \in A\), \(h(a) < h(v)\).

In [1] they have also proved a significant result on graph decomposition that if a graph \(G\) with \(n\) edges admits a \(\gamma\)-labeling then the complete graph \(K_{2cn+1}\) can be cyclically decomposed into \(2cn + 1\) copies of the graph \(G\), where \(c\) is any positive integer.

Motivated by the result of Blinco et al [1], in this paper, we prove that the well-known almost-bipartite graph, the grid with an additional edge, \((P_m \Box P_n) + \hat{e}\), admits \(\gamma\)-labeling. Further, we discuss a related open problem.

Bader Ali1, Abdullah Al Mutairi1, Paul Manuel1
1Bader Ali, Abdullah Al Mutairi, and Paul Manuel Department of Information Science, College of Computing Science and Engineering, Kuwait University, Kuwait
Abstract:

A set \( S \) of vertices of a graph \( G(V,E) \) is a \({dominating \;set}\) if every vertex of \( V \setminus S \) is adjacent to some vertex in \( S \). A dominating set is said to be \({efficient}\) if every vertex of \( V \setminus S \) is dominated by exactly one vertex of \( S \). A paired-dominating set is a dominating set whose induced subgraph contains at least one perfect matching. A set \( S \) of vertices in \( G \) is a total dominating set of \( G \) if every vertex of \( V \) is adjacent to some vertex in \( S \). In this paper, we construct a minimum paired dominating set and a minimum total dominating set for the infinite diamond lattice. The total domatic number of \( G \) is the size of a maximum cardinality partition of \( V \) into total dominating sets. We also demonstrate that the total domatic number of the infinite diamond lattice is 4.

Shannon Overbay1
1Department of Mathematics Gonzaga University, Spokane, WA, USA
Abstract:

In the classical book embedding problem, a \( k \)-book is defined to be a line \( L \) in \( 3 \)-space (the spine) together with \( k \) half-planes (the pages) joined together at \( L \). We introduce two variations on the classical book in which edges are allowed to wrap in either one or two directions. The first is a cylindrical book where the spine is a line \( L \) in \( 3 \)-space and the pages are nested cylindrical shells joined together at \( L \). The second is a torus book where the spine is the inner equator of a torus and the pages are nested torus shells joined together at this equator. We give optimal edge bounds for embeddings of finite simple graphs in cylinder and torus books and give best-possible embeddings of \( K_n \) in torus books. We also compare both books with the classical book.

Atif A. Abueida1, Courtney Perkinst1
1Department of Mathematics University of Dayton 300 College Park Dayton, OH 45469-2316
Abstract:

We give necessary and sufficient conditions for the decomposition of the complete graphs with multiple holes, \( K_n \setminus hK_v \), into the graph-pair of order \( 4 \).

Mark Anderson1, Julie R. Carrington1, Robert C. Brigham2, Ronald D.Dutton3, Richard P. Vitray1
1Department of Mathematics and Computer Science, Rollins College, Winter Park, FL 32789
2Department of Mathematics, University of Central Florida, Orlando, FL 32816
3Computer Science, University of Central Florida, Orlando, FL 32816
Abstract:

A vertex cover of a graph \( G = (V, E) \) is a subset \( S \subseteq V \) such that every edge is incident with at least one vertex in \( S \), and \( \alpha(G) \) is the cardinality of a smallest vertex cover. Let \( \mathcal{T} \) be a collection of vertex covers, not necessarily minimum. We say \( \mathcal{T} \) is closed if for every \( S \in \mathcal{T} \) and every \( e \in E \) there is a one-to-one function \( f : S \to V \) such that (1) \(f(S)\) is a vertex cover,(2) for some \(s \in S\), \(\{s, f(s)\} = e\), (3)for each \(s\) in \(S\), either \(s = f(s)\) or \(s\) is adjacent to \(f(s)\), and (4) \(f(S) \in \mathcal{T}\).A set is an eternal vertex cover if and only if it is a member of some closed family of vertex covers. The cardinality of a smallest eternal vertex cover is denoted \( \alpha_m^\infty(G) \). Eternal total vertex covers are defined similarly, with the restriction that the cover must also be a total dominating set. The cardinality of a smallest eternal total vertex cover is denoted \( \alpha_{mt}^\infty(G) \). These three vertex cover parameters satisfy the relation \(\alpha(G) \leq \alpha_{m}^\infty(G) \leq \alpha_{mt}^\infty(G) \leq 2\alpha(G).\) We define a triple \( (p, q, r) \) of positive integers such that \( p \leq q \leq r \leq 2p \) to be feasible if there is a connected graph \( G \) such that \( \alpha(G) = p \), \( \alpha_{m}^\infty(G) = q \), and \( \alpha_{mt}^\infty(G) = r \). This paper shows all triples with the above restrictions are feasible if \( p \neq q \) or \( r \leq \frac{3p}{2} \) and conjectures that there are no feasible triples of the form \( (p, p, r) \) with \( r > \frac{3p}{2} \). The graphs with triple \( (p, p + 1, 2p) \) are characterized and issues related to the conjecture are discussed.

M. Mohammad-Noori 1,2
1Department of Mothematics, Statistics and Computer Science, University of Tehran, P.O. Boz 14155-6455, Tehran, fran
2School of Computer Science, Institute for Research in Fundamental Sciences (IPM), P.O. Box: 19395-5746, Tehran, fran
Abstract:

We study the area distribution of closed walks of length \( n \), starting and ending at the origin. The concept of algebraic area of a walk in the square lattice is slightly modified and the usefulness of this concept is demonstrated through a simple argument. The idea of using a generating function of the form \( (x + x^{-1} + y + y^{-1})^n \) to study these walks is then discussed from a special viewpoint. Based on this, a polynomial time algorithm for calculating the exact distribution of such walks for a given length is concluded. The presented algorithm takes advantage of the Chinese remainder theorem to overcome the problem of arithmetic with large integers. Finally, the results of the implementation are given for \( n = 32, 64, 128 \).

Guodong Liu1, Jing Xu1
1College of Computer and Control Engineering Nankai University, Tianjin 300071, China
Abstract:

The Wiener polarity index of a graph \( G \) is the number of unordered pairs of vertices \( u, v \) such that the distance between \( u \) and \( v \) is three, which was introduced by Harold Wiener in 1947. A linear time algorithm for computing the Wiener polarity index of trees was described, and also an algorithm which computes the index \( W_p(G) \) for any given connected graph \( G \) on \( n \) vertices in time \( O(M(n)) \) was presented, where \( M(n) \) denotes the time necessary to multiply two \( n \times n \) matrices of small integers (which is currently known to be \( O(n^{2.376}) \)). In this paper, we establish one polynomial algorithm to calculate the value of the Wiener polarity index of a bipartite graph.

Amy Baer1, Brenda Johnson Mammenga2, Christopher Spicer2
1Morningside College Sioux City, IA 51106
2Department of Mathematical Sciences Morningside College Sioux City, IA 51106
Abstract:

Rado numbers are closely related to Ramsey numbers, but pertaining to equations and integers instead of cliques within graphs. For every integer \( m \geq 3 \) and every integer \( c \), let the 2-color Rado number \( r(m,c) \) be the least integer, if it exists, such that for every 2-coloring of the set \( \{1,2,\ldots,r(m,c)\} \) there exists a monochromatic solution to the equation \(\sum_{i=1}^{m-1} x_i + c = x_m\) .The values of \( r(m,c) \) have been determined previously for nonnegative values of \( c \), as well as all values of \( m \) and \( c \) such that \( -m+2 < c < 0 \) and \( c < -(m-1)(m-2) \). In this paper, we find \( r(m,c) \) for the remaining values of \( m \) and \( c \).

Elie Feder1, David Garber2
1Kingsborough Community College of CUNY, Department of Mathematics and Computer Science, 2001 Oriental Blvd., Brooklyn, NY 11235, USA
2Department of Applied Mathematics, Faculty of Sciences, Holon Institute of Technology, 52 Golomb St., PO Box 305, Holon 58102, Israel and (Sabbatical:) Einstein Institute of Mathematics, Hebrew University of Jerusalem, Jerusalem, Israel
Abstract:

This paper deals with the Orchard crossing number of some families of graphs which are based on cycles. These include disjoint cycles, cycles which share a vertex and cycles which share an edge. Specifically, we focus on the prism and ladder graphs.

Wei Gao1, Tianwei Xu1, Li Liang1, Juxiang Zhou2
1School of Information Science and Technology, Yunnan Normal University, Kunming 650500, China
2Key Laboratory of Educational Informatization for Nationalities, Ministry of Education, Yunnan Normal University, Kunming 650500, China
Abstract:

Let \(i(G)\) be the number of isolated vertices in graph \(G\). The isolated toughness of \(G\) is defined as \(I(G) = +\infty\) if \(G\) is complete; \(I(G) = \text{min}\{|S|/i(G-S) : S \subseteq V(G), i(G-S) \geq 2\}\) otherwise. In this paper, we determine that \(G\) is a fractional \((g, f, n)\)-critical graph if \(I(G) \geq \frac{b^2 + bn – 1}{a}\) if \(b > a\); \(I(G) \geq b + n\) if \(a = b\).

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