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.

Jinhua Wang1
1 School of Sciences, Nantong University Nantong 226007, P. R. China
Abstract:

Let \(\lambda K_{h^u}\) denote the \(\lambda\)-fold complete multipartite graph with \(u\) parts of size \(h\). A cube factorization of \(\lambda K_{h^u}\) is a uniform \(3\)-factorization of \(\lambda K_{h^u}\) in which the components of each factor are cubes. We show that there exists a cube factorization of \(\lambda K_{h^u}\) if and only if \(uh \equiv 0 \pmod{8}\), \(\lambda (u-1)h \equiv 0 \pmod{3}\), and \(u \geq 2\). It gives a new family of uniform \(3\)-factorizations of \(\lambda K_{h^u}\). We also establish the necessary and sufficient conditions for the existence of cube frames of \(\lambda K_{h^u}\).

G. Sethuraman1, K. Sankar1
1Department of Mathematics Anna University Chennai – 600 025 India
Abstract:

We recall from [13] a shell graph of size \(n\), denoted \(C(m,n-3)\), is the graph obtained from the cycle \(C_n(v_0,v_1,v_2\ldots,v_{n-1})\) by adding \(m-3\) consecutive chords incident at a common vertex, say \(v_0\). The vertex \(v_0\) of \(C(n,n-3)\) is called the apex of the shell \(C(n,n-3)\). The vertex \(v_0\) of \(C(n,n-3)\) is said to be at level \(l\).

A graph \(C(2n,n-2)\) is called an alternate shell, if \(C(2n,n-2)\) is obtained from the cycle \(C{2n}(v_0,v_1,v_2\ldots,v_{2n-1})\) by adding \(n-2\) chords between the vertex \(v_0\) and the vertices \(v_{2i-1}\) for \(1-i\delta n\). If the vertex \(v_i\) of \(C(2n,n-2)\) at level \(l\) and is adjacent with \(v_0\), then \(v_l\) is said to be at level \(l\) with a chord, otherwise the vertex \(v_i\) is said to be at level \(l\) without a chord.

A graph, denoted \(G{2n_i,n_i,2,k,l}\), is called one vertex union of alternate shells with a path at any common level \(l\) (with or without chords), if it is obtained from \(k\) alternate shells \(C(2n_i,n_i-2)’s\), \(1- i\delta k\), by merging them together at their apex and joining \(k\) vertices each chosen from a distinct alternate shell in a particular level \(l\) (with or without chords) by a path \(P_{2k-1}\), such that the chosen vertex of the \(i\)th alternate shell \(C(2n_i,n_i-2)\) is at the \((2i-1)\)th vertex of the \(P_{2k-l}\) for \(1- i\delta k\). We denote the graph \(G{2n_i,n_i,2,k,l}\) as \(G{2n_i,n_i,2,k,l_c}\) if the path \(P_{2k-1}\) joins the vertices only at the common level \(l\) with chords.

In this paper, we show that \(G{2n_i,n_i,2,k,l_c}\) is graceful and admits an \(A\)-labeling, for \(k-\tau1, n_i\), \( 3,1\tau1,n_i\), and \(G{2n_i,n_i,2,k,1}\) is cordial, for \(n_i-n-3 ,k-1,1\tau i\).

Wongsakorn Charoenpanitseri1,2, Narong Punnim3, Chariya Uiyyasathian2
1Department of Mathematics, Faculty of Science, Chulalongkorn University, Bangkok, 10330, Thailand
2Center of Excellent in Mathematics, CHE, Sri Ayutthaya Rd. Bangkok, 10400, Thailand.
3Department of Mathematics, Srinakharinwirot University, Sukhumvit 23, Bangkok 10110, Thailand
Abstract:

A \((k,t)\)-list assignment \(L\) of a graph \(G\) is a mapping which assigns a set of size \(k\) to each vertex \(v\) of \(G\) and \(|\bigcup_{v\in V(G)}L(v)| = t\). A graph \(G\) is \((k, t)\)-choosable if \(G\) has a proper coloring \(f\) such that \(f(v) \in L(v)\) for each \((k, t)\)-list assignment \(L\).

We determine \(t\) in terms of \(k\) and \(n\) that guarantee \((k, t)\)-choosability of any \(n\)-vertex graph and a better bound if such graph does not contain a \((k+1)\)-clique.

Yufa Shen1,2, Jun Guo3, Xin Xiao1, Qing Tang3
1Department of Mathematics, Hebei Normal University of Science and Technology, Qinhuangdao 066004, P.R. China
2Center for Mathematics of Hebei Province, Hebei Normal University, Shijiazhuang 050016, P.R. China
3Applied Mathematics Institute, Hebei University of Technology, Tianjin 300401, P.R. China
Abstract:

For paths \(P_n\), Chartrand, Nebesky and Zhang gave the exact value of \(ac'(P_n)\) for \(n \leq 8\), and showed that \(ac'(P_n) \leq \binom{n-2}{2}+2\) for every positive integer \(n\), where \(ac'(P_n)\) denotes the nearly antipodal chromatic number of \(P_n\). In this paper, we determine the exact values of \(ac'(P_n)\) for all even integers \(n \geq 8\).

Chin-Mei Fu1, Yu-Fong Hsu1, Wen-Chung Huang2
1Department of Mathematics Tamkang University, Tamsui, Taipei Shien, Taiwan, Republic of China
2Department of Mathematics Soochow University, Taipei, Taiwan, Republic of China.
Abstract:

A \(2\)-factor of a graph \(G\) is a \(2\)-regular spanning subgraph of \(G\) and a \(2\)-factorization of a graph \(G\) is a \(2\)-factor decomposition of \(G\). A complete solution to the problem of determining the spectrum of \(4\)-cycles in \(2\)-factorizations of the complete bipartite graph is presented.

Louis M.Friedler1
1Arcadia University Glenside, PA 19038
Abstract:

We study the independence number of the Cartesian product of binary trees and more general bipartite graphs. We give necessary and sufficient conditions on bipartite graphs under which certain upper and lower bounds on the independence number of the product are equal. A basic tool will be an algorithm for finding the independence number of a binary tree.

Chen Shangdi1, Zhao Dawei1
1College of Science, Civil Aviation University of China, Tianjin, 300300, PR.China,
Abstract:

Multireceiver authentication codes allow one sender to construct an authenticated message for a group of receivers such that each receiver can verify the authenticity of the received message. In this paper, we construct two multireceiver authentication codes from symplectic geometry over finite fields. The parameters and the probabilities of deceptions of the codes are also computed.

Iwao Sato1
1Oyama National College of Technology Oyama, Tochigi 323-0806, JAPAN
Abstract:

We give determinant expressions of the zeta function and an \(L\)-function of a semiregular weighted bipartite graph. As an application, we present a decomposition formula for the weighted complexity of a semiregular weighted bipartite graph.

Lili Hu1, Chunhui Lai1
1Department of Mathematics, Zhangzhou Teachers College, Zhangzhou, Fujian 363000, P. R. of CHINA.
Abstract:

In this paper, we characterize the potentially \((K_5 – C_4)\)-graphic sequences, where \(K_s – C_4\) is the graph obtained from \(K_5\) by removing four edges of a \(4\)-cycle \(C_4\). This characterization implies a theorem due to Lai \([6]\).

Adel T. Diab1
1 Faculty of Science, Department of Mathematics, Ain Shams University Abbassia, Cairo, Egypt.
Abstract:

A graph is said to be cordial if it has a \(0-1\) labeling that satisfies certain properties. The purpose of this paper is to generalize some known theorems and results of cordial graphs. Specifically, we show that certain combinations of paths, cycles, stars, and null graphs are cordial. Finally, we prove that the torus grids are cordial if and only if its size is not congruent to \(2\) \((mod 4)\).