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.

Faud Alsarari1
1Department of Mathematics, College of Sciences, Yanbu, Taibah University, Saudi Arabia
Abstract:

The aim of this paper is to introduce and study a new class of analytic functions which generalize the classes of \(\lambda\)-Spirallike Janowski functions. In particular, we gave the representation theorem, the right side of the covering theorem, starlikeness estimates and some properties related to the functions in the class \( S_\lambda ( T, H, F ) \).

Tewodros Amdeberhan1, Victor H. Moll1
1Department of Mathematics, Tulane University, New Orleans, LA 70118
Abstract:

criteria to verify log-convexity of sequences is presented. Iterating this criteria produces infinitely log-convex sequences. As an application, several classical examples of sequences arising in Combinatorics and Special Functions are presented. The paper concludes with a conjecture regarding coefficients of chromatic polynomials.

Andrew M. Thomas1
1Center for Applied Mathematics, Cornell University
Abstract:

We discuss the VC-dimension of a class of multiples of integers and primes (equivalently indicator functions) and demonstrate connections to prime counting functions. Additionally, we prove limit theorems for the behavior of an empirical risk minimization rule as well as the weights assigned to the output hypothesis in AdaBoost for these “prime-identifying” indicator functions, when we sample \( mn \) i.i.d. points uniformly from the integers \(\{2, \ldots, n\}\).

Toufik Mansour1, Andres R. Moreno2, José L. Ramírez2
1Department of Mathematics, University of Haifa, 3498838 Haifa, Israel
2Departamento de Matemáticas, Universidad Nacional de Colombia, Bogotá, Colombia
Abstract:

Integer compositions and related counting problems are a rich and ubiquitous topic in enumerative combinatorics. In this paper we explore the definition of symmetric and asymmetric peaks and valleys over compositions. In particular, we compute an explicit formula for the generating function for the number of integer compositions according to the number of parts, symmetric, and asymmetric peaks and valleys.

Mateus Alegri 1
1Department of Mathematics, DMAI, Federal University of Sergipe,, Itabaiana, Sergipe, Brazil
Abstract:

In this paper we show some identities come from the \( q \)-identities of Euler, Jacobi, Gauss, and Rogers-Ramanujan. Some of these identities relate the function sum of divisors of a positive integer \( n \) and the number of integer partitions of \( n \). One of the most intriguing results found here is given by the next equation, for \( n > 0 \),
\[
\sum_{l=1}^n \frac{1}{l!} \sum_{w_1+w_2+\cdots+w_l \in C(n)} \frac{\sigma_1(w_1) \sigma_1(w_2) \cdots \sigma_1(w_l)}{w_1 w_2 \cdots w_l} = p_1(n),
\]
where \( \sigma_1(n) \) is the sum of all positive divisors of \( n \), \( p_1(n) \) is the number of integer partitions of \( n \), and \( C(n) \) is the set of integer compositions of \( n \). In the last section, we show seven applications, one of them is a series expansion for
\[
\frac{(q^{a_1};q^{b_1})_\infty (q^{a_2};q^{b_2})_\infty \cdots (q^{a_k};q^{b_k})_\infty}
{(q^{c_1};q^{d_1})_\infty (q^{c_2};q^{d_2})_\infty \cdots (q^{c_r};q^{d_r})_\infty},
\]
where \( a_1, \ldots, a_k, b_1, \ldots, b_k, c_1, \ldots, c_r, d_1, \ldots, d_r \) are positive integers, and \( |q| < 1 \).

Dongwei Guo1, Wenchang Chu2
1School of Mathematics and Statistics Zhoukou Normal University Zhoukou (Henan), China
2Department of Mathematics and Physics University of Salento (P. O. Box 193) 73100 Lecce, Italy
Abstract:

Between Bernoulli/Euler polynomials and Pell/Lucas polynomials, convolution sums are evaluated in closed form via the generating function method. Several interesting identities involving Fibonacci and Lucas numbers are shown as consequences including those due to Byrd \( (1975) \) and Frontczak \( (2020) \).

Benjamin Garcia Morales1, Wai Yan Pong1
1California State University Dominguez Hills
Abstract:

The notion of length spectrum for natural numbers was introduced by Pong in \([5]\). In this article, we answer the question of how often one can recover a random number from its length spectrum. We also include a quick deduction of a result of LeVeque in \([4]\) on the average order of the size of length spectra.

Ben Lichtin 1
1Rochester, New York, USA
Abstract:

This paper uses exponential sum methods to show that if \( E \subset M_2(\mathbb{Z}/p^r) \) is a finite set of \( 2 \times 2 \) matrices with sufficiently large density and \( j \) is any unit in the finite ring \( \mathbb{Z}/p^r \), then there exist at least two elements of \( E \) whose difference has determinant \( j \).

Mouloud Goubi1
1Department of Mathematics, UMMTO University, 15000 Krim Belkacem, Tizi-Ouzou, Algeria, Laboratory of Algebra and Numbers Theory, USTHB Algiers
Abstract:

In this paper, we introduce a generalized family of numbers and polynomials of one or more variables attached to the formal composition \( f \cdot (g \circ h) \) of generating functions \( f \), \( g \), and \( h \). We give explicit formulae and apply the obtained result to two special families of polynomials; the first concerns the generalization of some polynomials applied to the theory of hyperbolic differential equations recently introduced and studied by \( M. \, Mihoubi \) and \( M. \, Sahari \). The second concerns two-variable Laguerre-based generalized Hermite-Euler polynomials introduced and should be updated to studied recently by \( N. \, U. \, Khan \, \textit{et al.} \).

Emanuele Munarini1
1Dipartimento di Matematica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Mi- lano, Italy
Abstract:

In this paper, we show that the generalized exponential polynomials and the generalized Fubini polynomials satisfy certain binomial identities and that these identities characterize the mentioned polynomials (up to an affine transformation of the variable) among the class of the normalized Sheffer sequences.

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