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.

Giorgio Ragusa1
1Dipartimento di Matematica e Informatica Universita di Catania viale A. Doria, 6 95125 Catania, Italia
Abstract:

Let \((X, \mathcal{B})\) be a \(\lambda\)-fold \(G\)-decomposition of \(\lambda H\). Let \(G_i\), \(i=1,\ldots,\mu\), be all nonisomorphic proper subgraphs of \(G\) without isolated vertices. Put \(\mathcal{B}_i = \{B_i \mid B \in \mathcal{B}\}\), where \(B_i\) is a subgraph of \(B\) isomorphic to \(G_i\). A complete simultaneous metamorphosis of \((X, \mathcal{B})\) is a rearrangement, for each \(i = 1, \ldots, \mu\), of the edges of \(\bigcup_{B \in \mathcal{B}} (E(B) \setminus E(B_i))\) into a family \(\mathcal{F}_i\) of copies of \(G_i\) with a leave \(L_i\), such that \((X, \mathcal{B}_i \cup \mathcal{F}_i, L_i)\) is a maximum packing of \(\lambda H\) with copies of \(G_i\). In this paper, we give a complete answer to the existence problem of a \(\lambda\)-fold kite system having a complete simultaneous metamorphosis.

Norman J. Finizio1, Sunra J.N. Mosconit2
1University of Rhode Island, Kingston, RI.
2Politecnico, Milano, Italy.
Abstract:

Whist tournaments for \( v \) players, \( \mathrm{Wh}(v) \), are known to exist for all \( v \equiv 0, 1 \pmod{4} \). In this paper, a new specialization of whist tournament design, namely a \({balanced\; whist\; tournament}\), is introduced. We establish that balanced whist tournaments on \( v \) players, \( \mathrm{BWh}(v) \), exist for several infinite classes of \( v \). An adaptation of a classic construction due to R. C. Bose and J. M. Cameron enables us to establish that \( \mathrm{BWh}(4n + 1) \) exist whenever \( 4n + 1 \) is a prime or a prime power. It is also established that \( \mathrm{BWh}(4n) \) exist for \( 4n = 2^k \), with \( k \equiv 0 \pmod{2, 3 \text{ or } 5} \). We demonstrate that a \( \mathrm{BWh}(4n + 1) \) is equivalent to a conference matrix of order \( 4n + 2 \). Consequently, a necessary condition for the existence of a \( \mathrm{BWh}(4n + 1) \) is that \( 4n + 1 \) is a product of primes each of which is \( \equiv 1 \pmod{4} \). Thus, in particular, \( \mathrm{BWh}(21) \) and \( \mathrm{BWh}(33) \) do not exist. Specific examples of \( \mathrm{BWh}(v) \) are given for \( v = 4, 8, 9, 20, 24, 32 \). It is also shown that a \( \mathrm{BWh}(12) \) does not exist.

Keith Neu1
1Science and Mathematics Division, Angelina College, 3500 South First Street, Lufkin, TX 75904, USA
Abstract:

Let \(\alpha(G)\) represent the maximal size of any product-free subset of a finite abelian group \(G\). It is well known that \(\alpha(G) = \frac{|G|}{3}\left(1 + \frac{1}{p}\right)\) if \(|G|\) is divisible by a prime \(p \equiv 2 \pmod{3}\) and \(p\) is the smallest such prime, \(\alpha(G) = \frac{|G|}{3}\) if \(|G|\) is not divisible by a prime \(p \equiv 2 \pmod{3}\) but \(3\) divides \(|G|\), and \(\alpha(G) = \frac{|G|}{3}\left(1 – \frac{1}{m}\right)\) if \(|G|\) is divisible only by primes \(p \equiv 1 \pmod{3}\) and \(m\) is the exponent of \(|G|\). In this paper, we use only basic group theory and number theory to derive exact expressions for the number of different maximal product-free subsets of \(G\) in the first two cases. The formulas are given in terms of the sizes of the subgroups of \(G\).

Manju K. Menon1, A. Vijayakumar1
1Department of Mathematics Cochin University of Science and Technology Cochin-682022, Kerala, India.
Abstract:

The \( P_3 \) intersection graph \( P_3(G) \) of a graph \( G \) is the intersection graph of all induced \( 3 \)-paths in \( G \). In this paper, we prove that any \( P_3 \)-convergent graph is \( P_3^n(G) \)-complete for some \( n \geq 1 \). Additionally, we prove that there are no \( P_3 \)-fixed graphs. The touching number, periodicity, and connectivity of \( P_3(G) \) are also studied.

O. Ascigil1, Y. Diao2, C. Erns3, D. High4, U. Ziegler5
1Department of Computer Science University of Kentucky Lexington, KY 40506
2Department of Mathematics University of North Carolina at Charlotte, Charlotte, NC 28223,
3Department of Mathematics Western Kentucky University Bowling Green, KY 42101
4Department of Mathematics Western Kentucky University Bowling Green, KY 42101,
5Department of Computer Science Western Kentucky University Bowling Green, KY 42101
Abstract:

This paper describes the study of a special class of 4-regular plane graphs that are Hamiltonian. These graphs are of particular interest in knot theory. An algorithm is presented that randomly generates such graphs with \( n \) vertices with a fixed (and oriented) Hamiltonian cycle in \( O(n) \) time. An exact count of the number of such graphs with \( n \) vertices is obtained, and the asymptotic growth rate of this number is determined. Numerical evidence is provided to show that the algorithm can be modified to generate these graphs with a near uniform probability. This can be considered a first step in generating large random knots without bias.

M.J. Grannell1, M. Knor2
1Department of Mathematics and Statistics The Open University Walton Hall, Milton Keynes MK7 6AA UNITED KINGDOM
2Department of Mathematics, Faculty of Civil Engineering Slovak University of Technology Radlinského 11, 813 68 Bratislava SLOVAKIA
Abstract:

We enumerate nonisomorphic minimum genus orientable embeddings of the complete bipartite graph \( K_{m,n} \) for \( 2 \leq m, n \leq 7 \) except for \( (m, n) = (7, 7) \).

Sizhong Zhou1
1School of Mathematics and Physics Jiangsu University of Science and Technology Mengxi Road 2, Zhenjiang, Jiangsu 212003 People’s Republic of China
Abstract:

A complete coloring of a graph \( G \) is a proper vertex coloring of \( G \) with the property that for every two distinct colors \( i \) and \( j \) used in the coloring, there exist adjacent vertices of \( G \) colored \( i \) and \( j \). The maximum positive integer \( k \) for which \( G \) has a complete \( k \)-coloring is the achromatic number \( \psi(G) \) of \( G \).

A Grundy coloring of a graph \( G \) is a proper vertex coloring of \( G \) with the property that for every two colors (positive integers) \( i \) and \( j \) with \( i < j \), every vertex colored \( j \) has a neighbor colored \( i \). The maximum positive integer \( k \) for which a graph \( G \) has a Grundy \( k \)-coloring is the Grundy number \( \Gamma(G) \). Thus, \( 2 \leq \chi(G) \leq \Gamma(G) \leq \psi(G) \) for every nonempty graph \( G \). It is shown that if \( a, b, \) and \( c \) are integers with \( 2 \leq a \leq b \leq c \), then there exists a connected graph \( G \) with \( \chi(G) = a \), \( \Gamma(G) = b \), and \( \psi(G) = c \) if and only if \( a = b = c = 2 \) or \( b \geq 3 \).

Gary Chartrand1, Futaba Okamoto2, Zsolt Tuza3, Ping Zhang4
1Department of Mathematics Western Michigan University Kalamazoo, MI 49008, USA
2Mathematics Department University of Wisconsin – La Crosse La Crosse, WI 54601, USA
3Computer and Automation Institute Hungarian Academy of Sciences Budapest, HUNGARY
4Department of Mathematics Western Michigan University Kalamazeo, MI 49008, U
Abstract:

A complete coloring of a graph \( G \) is a proper vertex coloring of \( G \) with the property that for every two distinct colors \( i \) and \( j \) used in the coloring, there exist adjacent vertices of \( G \) colored \( i \) and \( j \). The maximum positive integer \( k \) for which \( G \) has a complete \( k \)-coloring is the achromatic number \( \psi(G) \) of \( G \).

A Grundy coloring of a graph \( G \) is a proper vertex coloring of \( G \) with the property that for every two colors (positive integers) \( i \) and \( j \) with \( i < j \), every vertex colored \( j \) has a neighbor colored \( i \). The maximum positive integer \( k \) for which a graph \( G \) has a Grundy \( k \)-coloring is the Grundy number \( \Gamma(G) \). Thus, \( 2 \leq \chi(G) \leq \Gamma(G) \leq \psi(G) \) for every nonempty graph \( G \). It is shown that if \( a, b, \) and \( c \) are integers with \( 2 \leq a \leq b \leq c \), then there exists a connected graph \( G \) with \( \chi(G) = a \), \( \Gamma(G) = b \), and \( \psi(G) = c \) if and only if \( a = b = c = 2 \) or \( b \geq 3 \).

Mustapha Chellali1, Odile Favaron2, Adriana Hansberg3, Lutz Volkmann3
1Department of Mathematics, University of Blida B.P. 270, Blida, Algeria
2L.R.1., URM 8623, Bat. 490, Université de Paris-Sud 91405-Orsay cedex, France
3Lehrstuhl II fir Mathematik, RWTH Aachen University 52056 Aachen, Germany
Abstract:

Let \( G \) be a simple graph, and let \( p \) be a positive integer. A subset \( D \subseteq V(G) \) is a \( p \)-dominating set of the graph \( G \) if every vertex \( v \in V(G) – D \) is adjacent to at least \( p \) vertices of \( D \). The \( p \)-domination number \( \gamma_p(G) \) is the minimum cardinality among the \( p \)-dominating sets of \( G \). Note that the \( 1 \)-domination number \( \gamma_1(G) \) is the usual domination number \( \gamma(G) \).

A subset \( S \subseteq V(G) \) is said to be a total dominating set if every vertex in \( V(G) \) has at least one neighbor in \( S \), and it is a connected dominating set if the graph induced by \( S \) is connected. The total domination number \( \gamma_t(G) \) represents the cardinality of a minimum total dominating set of \( G \) and the connected domination number \( \gamma_c(G) \) the cardinality of a minimum connected dominating set.

Fink and Jacobson showed in 1985 that if \( G \) is a graph with \( \Delta(G) \geq p \geq 2 \), then \(\gamma_p(G) \geq \gamma(G) + p – 2.\)
In this paper, we will give some sufficient conditions for a graph \( G \) such that \(\gamma_p(G) \geq \gamma(G) + p – 1.\)
We will show that for block graphs \( G \) the inequality \(\gamma_p(G) \geq \gamma_t(G) + p – 2 \) is valid and that for trees \( T \) the inequality \(\gamma_p(T) \geq \gamma_c(T) + p – 1\) holds. Further, we characterize the trees \( T \) with \(\gamma_p(T) = \gamma_c(T) + p – 1,\) \(\gamma_p(T) = \gamma_t(T) + p – 2, \gamma_p(T) = \gamma_t(T) + p – 1,\) and \(\gamma_p(T) = \gamma(T) + p – 1.\)

S. Arumugam1, C. Sivagnanam2
1Core Group Research Facility (CGRF) National Centre for Advanced Research in Discrete Mathematics (n-CARDMATH) Kalasalingam University Anand Nagar, Krishnankoil-626190, INDIA.
2Department of Mathematics St. Joseph’s College of Engineering Chennai-600119, INDIA,
Abstract:

Let \( G = (V, E) \) be a connected graph. A dominating set \( S \) of \( G \) is called a neighborhood connected dominating set (\({ncd-set}\)) if the induced subgraph \( \langle N(S) \rangle \) is connected. The minimum cardinality of an ncd-set of \( G \) is called the neighborhood connected domination number of \( G \) and is denoted by \( \gamma_{nc}(G) \). In this paper, we initiate a study of this parameter.

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