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Ptolemy Scientific Research Press (PSR Press)is a highly regarded publisher of scientific literature dedicated to bringing the latest research and findings to a broader audience. With a focus on cutting-edge research and technology, Ptolemy Scientific Research Press offers a range of publications catering to professionals, researchers, and student’s needs. Whether looking for information on the latest breakthroughs in physics, biology, engineering, or computer science, you can trust Ptolemy Scientific Research Press to deliver insightful, accurate, and engaging content. With its commitment to quality, accessibility, and innovation, Ptolemy Scientific Research Press is an essential resource for anyone interested in science and technology.

Latest Published Articles

Modelling the dynamics of multi-strain COVID-19 transmission

OMS-Vol. 7 (2023), Issue 1, pp. 269-278 Open Access Full-Text PDF

Joel N. Ndam and Stephen T. Agba

Abstract: It is on record that rolling out COVID-19 vaccines has been one of the fastest for any vaccine production worldwide. Despite this prompt action taken to mitigate the transmission of COVID-19, the disease persists. One of the reasons for the persistence of the disease is that the vaccines do not confer immunity against the infections. Moreover, the virus-causing COVID-19 mutates, rendering the vaccines less effective on the new strains of the disease. This research addresses the multi-strains transmission dynamics and herd immunity threshold of the disease. Local stability analysis of the disease-free steady state reveals that the pandemic can be contained when the basic reproduction number, \(R_{0}\) is brought below unity. The results of numerical simulations also agree with the theoretical results. The herd immunity thresholds for some of the vaccines against COVID-19 were computed to guide the management of the disease. This model can be applied to any strain of the disease.

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Results on the growth of solutions of complex linear differential equations with meromorphic coefficients

OMS-Vol. 7 (2023), Issue 1, pp. 248-268 Open Access Full-Text PDF

Mansouria Saidani and Benharrat Belaïdi

Abstract:The purpose of this paper is the study of the growth of solutions of higher order linear differential equations \(f^{\left( k\right) }+\left( A_{k-1,1}\left( z\right) e^{P_{k-1}\left(z\right) }+A_{k-1,2}\left( z\right) e^{Q_{k-1}\left( z\right) }\right)f^{\left( k-1\right) }+\cdots +\left( A_{0,1}\left( z\right) e^{P_{0}\left( z\right)
}+A_{0,2}\left( z\right) e^{Q_{0}\left( z\right) }\right) f=0\) and \(f^{\left( k\right) }+\left( A_{k-1,1}\left( z\right) e^{P_{k-1}\left(z\right) }+A_{k-1,2}\left( z\right) e^{Q_{k-1}\left( z\right) }\right)f^{\left( k-1\right) }+\cdots +\left( A_{0,1}\left( z\right) e^{P_{0}\left( z\right)}+A_{0,2}\left( z\right) e^{Q_{0}\left( z\right) }\right) f=F\left( z\right),\) where \(A_{j,i}\left( z\right) \left( \not\equiv 0\right) \left(j=0,…,k-1;i=1,2\right) ,\) \(F\left( z\right) \) are meromorphic functions of finite order and \(P_{j}\left( z\right) ,Q_{j}\left( z\right) \) \((j=0,1,…,k-1;i=1,2)\) are polynomials with degree \(n\geq 1\). Under some others conditions, we extend the previous results due to Hamani and Belaïdi [1].

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On 2-noncrossing increasing trees

ODAM-Vol. 6 (2023), Issue 2, pp. 39 – 50 Open Access Full-Text PDF

Isaac Owino Okoth

Abstract:A \(2\)-noncrossing tree is a rooted tree drawn in the plane with its vertices (colored black or white) on the boundary of a circle such that the edges are line segments that do not intersect inside the circle and there is no black-black ascent in any path from the root. A rooted tree is said to be increasing if the labels of the vertices are increasing as one moves away from the root. In this paper, we use generating functions and bijections to enumerate \(2\)-noncrossing increasing trees by the number of blacks vertices and by root degree. Bijections with noncrossing trees, ternary trees, 2-plane trees, certain Dyck paths, and certain restricted lattice paths are established.

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Introduction to total chromatic vertex stress of graphs

ODAM-Vol. 6 (2023), Issue 2, pp. 32 – 38 Open Access Full-Text PDF

Johan Kok

Abstract:This paper introduces the new notion of total chromatic vertex stress of a graph. Results for certain tree families and other \(2\)-colorable graphs are presented. The notions of chromatically-stress stability and chromatically-stress regularity are also introduced. New research avenues are also proposed.

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Arc coloring of odd graphs for hamiltonicity

ODAM-Vol. 6 (2023), Issue 2, pp. 14 – 31 Open Access Full-Text PDF

Italo Dejter

Abstract:Coloring the arcs of biregular graphs was introduced with possible applications to industrial chemistry, molecular biology, cellular neuroscience, etc. Here, we deal with arc coloring in some non-bipartite graphs. In fact, for \(1< k \in\mathbb{Z}\), we find that the odd graph \(O_k\) has an arc factorization with colors \(0,1,\ldots,k\) such that the sum of colors of the two arcs of each edge equals \(k\). This is applied to analyzing the influence of such arc factorizations in recently constructed uniform 2-factors in \(O_k\) and in Hamilton cycles in \(O_k\) as well as in its double covering graph known as the middle-levels graph \(M_k\).

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More on second Zagreb energy of graphs

ODAM-Vol. 6 (2023), Issue 2, pp. 7 – 13 Open Access Full-Text PDF

Mitesh J. Patel, Kajal S. Baldaniya and Ashika Panicker

Abstract:Let \(G\) be a graph with \(n\) vertices. The second Zagreb energy of graph \(G\) is defined as the sum of the absolute values of the eigenvalues of the second Zagreb matrix of graph \(G\). In this paper, we derive the relation between the second Zagreb matrix and the adjacency matrix of graph \(G\) and derive the new upper bound for the second Zagreb energy in the context of trace. We also derive the second Zagreb energy of \(m-\)splitting graph and \(m-\)shadow graph of a graph.

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BOOK-foundations-of-mathematical-analysis-and-semigroups-theory

BOOK - NULL CONTROLLABILITY OF DEGENERATE AND NON-DEGENERATE SINGULAR PARABOLIC