Online Journal of Analytic Combinatorics

ISSN 1931-3365 (online)

The Online Journal of Analytic Combinatorics (OJAC) is a peer-reviewed electronic journal, originally hosted by the University of Rochester and now published by Combinatorial Press. The journal provides a high-quality platform for research at the intersection of analysis, number theory, and combinatorics, with particular emphasis on the convergence and interplay of these disciplines.
Open Access: OJAC follows the Diamond Open Access model—completely free for both authors and readers, with no APCs
Publication Frequency: The journal publishes articles on a continuous publication model, ensuring that accepted papers appear online promptly once finalized.
Scope: OJAC publishes research at the interface of analysis, number theory, and combinatorics, with a particular focus on the interplay and convergence of these fields. 
Indexing & Abstracting: Indexed in MathSciNet, zbMATH, and Scopus, ensuring strong visibility and scholarly recognition within the global mathematical community.
Rapid Publication: Accepted papers are published online immediately after final acceptance, providing timely access to new research findings.
Online Editions: OJAC is published exclusively in online format, reflecting its fully digital and open-access mission.

Jop Briët1
1CWI, Science Park 123, 1098 XG Amsterdam, The Netherlands
Abstract:

It is shown that if \( V \subseteq \mathbb{F}_p^{n \times \cdots \times n} \) is a subspace of \( d \)-tensors with dimension at least \( tn^{d-1} \), then there is a subspace \( W \subseteq V \) of dimension at least \( t / (dr) – 1 \) whose nonzero elements all have analytic rank \( \Omega_{d, p}(r) \). As an application, we generalize a result of Altman on Szemerédi’s theorem with random differences.

István Mező1, Victor H. Moll2, José Ramírez3, Diego Villamizar2
1School of Mathematics and Statistics, Nanjing University of Information Science and Tech- nology, Nanjing, 210044, P. R. China
2Department of Mathematics, Tulane University, New Orleans, LA 70118
3Departamento de Matemáticas, Universidad Nacional de Colombia, Bogotá, Colombia
Abstract:

Extensions of a set partition obtained by imposing bounds on the size of the parts and the coloring of some of the elements are examined. Combinatorial properties and the generating functions of some counting sequences associated with these partitions are established. Connections with Riordan arrays are presented.

Abstract:

Every set of natural numbers determines a generating function convergent for \( q \in (-1, 1) \) whose behavior as \( q \to 1^- \) determines a germ. These germs admit a natural partial ordering that can be used to compare sets of natural numbers in a manner that generalizes both cardinality of finite sets and density of infinite sets. For any finite set \( D \) of positive integers, call a set \( S \) “\( D \)-avoiding” if no two elements of \( S \) differ by an element of \( D \). We study the problem of determining, for fixed \( D \), all \( D \)- avoiding sets that are maximal in the germ order. In many cases, we can show that there is exactly one such set. We apply this to the study of one-dimensional packing problems.

Sung Sik U1, Kyu Song Chae1
1Faculty of Mathematics, Kim Il Sung University, Pyongyang, Democratic People’s Republic of Korea
Abstract:

We prove some combinatorial identities by an analytic method. We use the property that singular integrals of particular functions include binomial coefficients. In this paper, we prove combinatorial identities from the fact that two results of the particular function calculated as two ways using the residue theorem in the complex function theory are the same. These combinatorial identities are the generalization of a combinatorial identity that has been already obtained

Aubrey Blecher1, Charlotte Brennan1, Arnold Knopfmacher1
1The John Knopfmacher Centre for Applicable Analysis and Number Theory, School of Math- ematics, University of the Witwatersrand, Private Bag 3, Wits 2050, Johannesburg, South Africa
Abstract:

Bargraphs are column convex polyominoes, where the lower edge lies on a horizontal axis. We consider the inner site-perimeter, which is the total number of cells inside the bargraph that have at least one edge in common with an outside cell and obtain the generating function that counts this statistic. From this we find the average inner perimeter and the asymptotic expression for this average as the semi-perimeter tends to infinity. We finally consider those bargraphs where the inner site-perimeter is exactly equal to the area of the bargraph.

Akbar Jahanbani 1, Hajar Shooshtari 1
1Department of Mathematics, Azarbaijan Shahid Madani University, Tabriz 51368, Iran
Abstract:

Let \( G \) be a graph with \( n \) vertices, then the \( c \)-dominating matrix of \( G \) is the square matrix of order \( n \) whose \( (i, j) \)-entry is equal to 1 if the \( i \)-th and \( j \)-th vertex of \( G \) are adjacent, is also equal to 1 if \( i = j \), \( v_i \in D_c \), and zero otherwise.

The \( c \)-dominating energy of a graph \( G \), is defined as the sum of the absolute values of all eigenvalues of the \( c \)-dominating matrix.

The main purposes of this paper are to introduce the \( c \)-dominating Estrada index of a graph. Moreover, to obtain upper and lower bounds for the \( c \)-dominating Estrada index and investigate the relations between the \( c \)-dominating Estrada in

Ramy Shaheen1, Suhail Mahfud1, Qays Alhawat1
1Department of Mathematics, Faculty of Science Tishreen University, Lattakia, Syria.
Abstract:

Let \( G(V,E) \) be a simple connected graph with vertex set \( V \) and edge set \( E \). The Wiener index in the graph is \(W(G) = \sum_{\{u,v\} \subseteq V} d(u,v),\) where \( d(u,v) \) is the distance between \( u \) and \( v \), and the Hosoya polynomial of \( G \) is \(H(G, x) = \sum_{\{u,v\} \subseteq V} x^{d(u,v)}.\) The hyper-Wiener index of \( G \) is \(WW(G) = \frac{1}{2} \left( W(G) + \sum_{\{u,v\} \subseteq V} d^2(u,v) \right).\) In this paper, we compute the Wiener index, Hosoya polynomial, and hyper-Wiener index of Jahangir graph \( J_{8,m} \) for \( m \geq 3 \).

Anetta Szynal-Liana1, Iwona Włoch 1
1Faculty of Mathematics and Applied Physics, Rzeszow University of Technology, al. Powstanców ´ Warszawy 12, 35-959 Rzeszów, Poland
Abstract:

Hybrid numbers are generalization of complex, hyperbolic and dual numbers. In this paper we introduce and study Fibonacci-Pell hybrinomials, i.e. polynomials, which are a generalization of hybrid numbers of the Fibonacci type.

Sultan Senan Mahde1, Veena Mathad1
1Department of Studies in Mathematics, University of Mysore, Manasagangotri, Mysuru , India
Abstract:

The hub-integrity of a graph is given by the minimum of \( |S| + m(G – S) \), where \( S \) is a hub set and \( m(G – S) \) is the maximum order of the components of \( G – S \). In this paper, the concept of hub edge-integrity is introduced as a new measure of the stability of a graph \( G \), and it is defined as \(HEI(G) = \min\{|S| + m(G – S)\},\) where \( S \) is an edge hub set and \( m(G – S) \) is the order of a maximum component of \( G – S \). Furthermore, an \( HEI \)-set of \( G \) is any set \( S \) for which this minimum is attained. Several properties and bounds on the \( HEI \) are presented, and the relationship between \( HEI \) and other parameters is investigated. The \( HEI \) of some classes of graphs is also computed.

Ali Ahmad1
1College of Computer Science and Information Technology,, Jazan University, Jazan, Saudi Arabia.
Abstract:

A graph \( G(R) \) is said to be a zero divisor graph of a commutative ring \( R \) with identity if \( x_1, x_2 \in V(G(R)) \) and \( (x_1, x_2) \in E(G(R)) \) if and only if \( x_1 \cdot x_2 = 0 \). The vertex-degree-based eccentric topological indices of zero divisor graphs of commutative rings \( \mathbb{Z}_{p^2} \times \mathbb{Z}_{q^2} \) are studied in this paper, with \( p \) and \( q \) being primes.

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