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.

Sapna Jain1
1Department of Mathematics University of Delhi Delhi 110 007 India
Abstract:

In this paper, we generalize the notion of solid bursts from classical codes equipped with Hamming metric \([14]\) to array codes endowed with RT-metric \([13]\) and obtain some bounds on the parameters of RT-metric array codes for the correction and detection of solid burst array errors.

Yuchao Li1, Junfeng Du1, Jianhua Tu1
1School of Science Beijing University of Chemical Technology, Beijing 100029, China
Abstract:

Given a graph \(G = (V,E)\), a matching \(M\) of \(G\) is a subset of \(E\), such that every vertex of \(V\) is incident to at most one edge of \(M\). A \(k\)-matching is a matching with \(k\) edges. The total number of matchings in \(G\) is used in chemoinformatics as a structural descriptor of a molecular graph. Recently, Vesalian and Asgari (MATCH Commun. Math. Comput. Chem. \(69 (2013) 33–46\)) gave a formula for the number of \(5\)-matchings in triangular-free and \(4\)-cycle-free graphs based on the degrees of vertices and the number of vertices, edges, and \(5\)-cycles. But, many chemical graphs are not triangular-free or \(4\)-cycle-free, e.g., boron-nitrogen fullerene graphs (or BN-fullerene graphs). In this paper, we take BN-fullerene graphs into consideration and obtain formulas for the number of \(5\)-matchings based on the number of hexagons.

M.Ali Özarslan1, Cem Kaanoglu2
1astern Mediterranean University, Faculty of Arts and Sciences, Department of Mathematics, Gazimagusa, Mersin 10, Turkey
2Cyprus International University, Faculty of Engineering, Lefkoga, Mersin 10, Turkey
Abstract:

This paper aims to provide a systematic investigation of the family of polynomials generated by the Rodrigues’ formulas
\[K_{n_1,n_2}^{(\alpha_1, \alpha_2)}(x, k,p) = (-1)^{n_1+n_2} e^{px^k}[\prod\limits_{j=1}^2x^{-\alpha}\frac{d^nj}{dx^{n_j}} (x)^{\alpha_j+n_j}]e^{-px^k},\]
and
\[M_{n_1,n_2}^{(\alpha_0,p_1,p_2)}(x, k) = \frac{(-1)^{n_1+n_2}}{p_1^{n_1}p_2^{p_2}}x^{-\alpha_0}[\prod\limits_ {j=1}^{2}e^{p_jx^k}\frac{d^nj}{dx^{n_j}}{dx^{n_j}}e^{-p_jx^k}]x^{n_1+n_2+\alpha_0},\]
These polynomials include the multiple Laguerre and the multiple Laguerre-Hahn polynomials, respectively. The explicit forms, certain operational formulas involving these polynomials with some applications, and linear generating functions for \(K_{n_1,n_2}^{(\alpha_1, \alpha_2)}(x, k,p)\) and \(M_{n_1,n_2}^{(\alpha_0,p_1,p_2)}(x, k)\) are obtained.

Xin Xie1, Jun-Ming Xu2
1Department of Mathematics, Huangshan University Huangshan, 245041, China
2Department of Mathematics, University of Science and Technology of China Hefei, 230026, China
Abstract:

For an \(n\)-connected graph \(G\), the \(n\)-wide diameter \(d_n(G)\), is the minimum integer \(m\) such that there are at least \(n\) internally disjoint \((di)\)paths of length at most \(m\) between any vertices \(x\) and \(y\). For a given integer \(l\), a subset \(S\) of \(V(G)\) is called an \((l, n)\)-dominating set of \(G\) if for any vertex \(x \in V(G) – S\) there are at least \(n\) internally disjoint \((di)\)paths of length at most \(l\) from \(S\) to \(z\). The minimum cardinality among all \((l, n)\)-dominating sets of \(G\) is called the \((l, n)\)-domination number. In this paper, we obtain that the \((l, n)\)-domination number of the \(d\)-ary cube network \(C(d, n)\) is \(2\) for \(1 \leq w \leq d\) and \(d_w(G) – f(d, n) \leq l \leq d_w(G) – 1 \) if \(d,n\geq 4\), where \(f(d, n) = \min\{e(\left\lfloor \frac{n}{2} \right\rceil + 1), \left\lfloor \frac{n}{2} \right\rfloor e\}\).

O. Favaron1, S.M. Sheikholeslami2, L. Volkmann3
1Univ Paris-Sud and CNRS, LRI, UMR 8623 Orsay, F-91405, France
2Department of Mathematics Azarbaijan University of Tarbiat Moallem Tabriz, I-R. Iran
3Lehrstuhl II fiir Mathematik RWTH Aachen University 52056 Aachen, Germany
Abstract:

Let \(k\) be a positive integer, and let \(G\) be a simple graph with vertex set \(V(G)\). A function \(f: V(G) \rightarrow \{-1, 1\}\) is called a signed \(k\)-dominating function if \(\sum_{u \in N(v)} f(u) \geq k\) for each vertex \(v \in V(G)\). A set \(\{f_1, f_2, \ldots, f_d\}\) of signed \(k\)-dominating functions on \(G\) with the property that \(\sum_{i=1}^{d} f_i(v) \leq 1\) for each \(v \in V(G)\), is called a signed \(k\)-dominating family (of functions) on \(G\). The maximum number of functions in a signed \(k\)-dominating family on \(G\) is the signed \(k\)-domatic number of \(G\), denoted by \(d_{kS}(G)\). In this paper, we initiate the study of signed \(k\)-domatic numbers in graphs and we present some sharp upper bounds for \(d_{kS}(G)\). In addition, we determine the signed \(k\)-domatic number of complete graphs.

Qing Liu1, Zhishan Liu2
1 School of Statistics and Research Center of Applied Statistics Jiangxi University of Finance and Economics, Nanchang, 330013, P.R.China
2 Department of Mathematics, Yang-en University, Quanzhou, 362014, P.R.China
Abstract:

In this paper, \(E_2\)-cordiality of a graph \(G\) is considered. Suppose \(G\) contains no isolated vertex, it is shown that \(G\) is \(E_2\)-cordial if and only if \(G\) is not of order \(4n + 2\).

Ting-Pang Chang1, Li-Da Tong1
1Department of Applied Mathematics, National Sun Yat-sen University, Kaohsiung 804, Taiwan
Abstract:

A Hamiltonian walk of a connected graph \(G\) is a closed spanning walk of minimum length in \(G\). The length of a Hamiltonian walk in \(G\) is called the Hamiltonian number, denoted by \(h(G)\). An Eulerian walk of a connected graph \(G\) is a closed walk of minimum length which contains all edges of \(G\). In this paper, we improve some results in [5] and give a necessary and sufficient condition for \(h(G) < e(G)\). Then we prove that if two nonadjacent vertices \(u\) and \(v\) satisfying that \(\deg(u) + \deg(v) \geq |V(G)|\), then \(h(G) = h(G + uv)\). This result generalizes a theorem of Bondy and Chvatal for the Hamiltonian property. Finally, we show that if \(0 \leq k \leq n-2\) and \(G\) is a 2-connected graph of order \(n\) satisfying \(\deg(u) + \deg(v) + \deg(w) \geq \frac{3n+k-2}{2}\) for every independent set \(\{u,v,w\}\) of three vertices in \(G\), then \(h(G) \leq n+k\). It is a generalization of Bondy's result.

Yair Caro1, Leida Gonzalez2, Luz Elimar Marchan3, Oscar Ordazé4
1Department of Mathematics. University of Haifa-Oranim. Tivon-36006. Israel
2Departamento de MatemAticas and Laboratorio MoST Centro ISYS, Facultad de Ciencias, Universidad Central de Venezuela, Ap. 47567, Caracas 1041-A, Venezuela.
3Departamento de Matemiaticas. Decanato de Ciencias y Tecnologfas, Universidad Centroccidental Lisandro Alvarado, Barquisimeto, Venezuela.
4Departamento de MatemAticas and Laboratorio MoST Centro ISYS, Facultad de Ciencias, Universidad Central de Venezuela, Ap. 47567, Caracas 1041-A, Venezuela. Corresponding author.
Abstract:

Let \(G\) be a finite abelian group of order \(n\). The barycentric Ramsey number \(BR(H,G)\) is the minimum positive integer \(r\) such that any coloring of the edges of the complete graph \(K_r\) by elements of \(G\) contains a subgraph \(H\) whose assigned edge colors constitute a barycentric sequence, i.e., there exists one edge whose color is the “average” of the colors of all edges in \(H\). When the number of edges \(e(H) \equiv 0 \pmod{\exp(G)}\), \(BR(H,G)\) are the well-known zero-sum Ramsey numbers \(R(H,G)\). In this work, these Ramsey numbers are determined for some graphs, in particular, for graphs with five edges without isolated vertices using \(G = \mathbb{Z}_n\), where \(2 \leq n \leq 4\), and for some graphs \(H\) with \(e(H) \equiv 0 \pmod{2}\) using \(G = \mathbb{Z}_2^s\).

Luc Lapierre1, Sean Mcguinness1
1Thompson Rivers University Kamloops, BC V2C0C8 Canada
Abstract:

Hrnciar and Haviar [3] gave a method to construct a graceful labeling for all trees of diameter at most five. Based on their method and the methods described in Balbuena et al. [1], we shall describe a new construction for gracefully labeled trees by attaching trees to the vertices of a tree admitting a bipartite graceful labeling.

Raluceca Gera1, Craig E.Larson2, Ryan Pepper3, Craig Rasmussen1
1Naval Postgraduate School, Department of Applied Mathematics, Monterey, CA 93943
2Department of Mathematics and Applied Mathematics, Richmond, VA 23284
3Department of Computer and Mathematical Sciences, Houston, TX 77002
Abstract:

Given two graphs \( G \) and \( H \) and a function \( f \subset V(G) \times V(H) \), Hedetniemi [9] defined the \emph{function graph} \( GfH \) by \( V(GfH) = V(G) \cup V(H) \) and \( E(GfH) = E(G) \cup E(H) \cup \{uv \mid v : f(u)\} \). Whenever \( G \cong H \), the function graph was called a functigraph by Chen, Ferrero, Gera, and Yi [7]. A function graph is a generalization of the \( \alpha \)-permutation graph introduced by Chartrand and Harary [5]. The independence number of a graph is the size of a largest set of mutually non-adjacent vertices. In this paper, we study independence number in function graphs. In particular, we give a lower bound in terms of the order and the chromatic number, which improves on some elementary results and has a number of interesting corollaries.

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