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
ODAM-Vol. 3 (2020), Issue 1, pp. 11 – 19 Open Access Full-Text PDF
Lihua Feng, Lu Lu, Dragan Stevanović
Abstract: For a given graph, let \(w_k\) denote the number of its walks with \(k\) vertices and let \(\lambda_1\) denote the spectral radius of its adjacency matrix. Nikiforov asked in [Linear Algebra Appl 418 (2006), 257–268] whether it is true in a connected bipartite graph that \(\lambda_1^r\geq\frac{w_{s+r}}{w_s}\) for every even \(s\geq 2\) and even \(r\geq 2\)? We construct here several infinite sequences of connected bipartite graphs with two main eigenvalues for which the ratio \(\frac{w_{s+r}}{\lambda_1^r w_s}\) is larger than~1 for every even \(s,r\geq 2\), and thus provide a negative answer to the above problem.
Extremal total eccentricity of \(k\)-apex trees
ODAM-Vol. 3 (2020), Issue 1, pp. 8 – 10 Open Access Full-Text PDF
Naveed Akhter, Hafiza Iqra Yasin
Abstract: In a simple connected graph \(G\), eccentricity of a vertex is one of the first, distance-based invariants. The eccentricity of a vertex \(v\) in a connected graph \(G\) is the maximum distance of the vertex \(v\) to any other vertex \(u\). The total eccentricity of the graph \(G\) is the sum of the all vertex eccentricities. A graph \(G\) is called an apex tree if it has a vertex \(x\) such that \(G-x\) is a tree. In this work we have found the graph having extremal total eccentricity of \(k\)-apex trees.
Antimagicness of subdivided fans
OMS-Vol. 4 (2020), Issue 1, pp. 18 – 22 Open Access Full-Text PDF
Afshan Tabassum, Muhammad Awais Umar, Muzamil Perveen, Abdul Raheem
Abstract: A graph \(\Gamma\) (simple, finite, undirected) with an \(\Omega\)-covering has an \((\alpha,\delta)\)-\(\Omega\)-antimagic labeling if the weights of all subgraphs \(\Omega\) of graph \(\Gamma\) constitute an arithmetic progression with the common difference \(\delta\). Such a~graph is called super \((\alpha,\delta)\)-\(\Omega\)-antimagic if \(\nu(V(\Gamma))= \{ 1,2,3,\dots,|V(\Gamma)|\}\). In the present paper, the cycle coverings of subdivision of fan graphs has been considered and results are proved for several differences.
Second Zagreb indices of transformation graphs and total transformation graphs
ODAM-Vol. 3 (2020), Issue 1, pp. 1 – 7 Open Access Full-Text PDF
Prashant V. Patil, Girish G. Yattinahalli
Abstract: In this paper, we obtained some new properties of Zagreb indices. We mainly give explicit formulas to the second Zagreb index of semitotal-line graph (or middle graph), semitotal-point graph and total transformation graphs \(G^{xyz}.\)
A unified integral operator and further its consequences
OMA-Vol. 4 (2020), Issue 1, pp. 1 – 7 Open Access Full-Text PDF
Ghulam Farid
Abstract: The aim of this paper is to construct left sided and right sided integral operators in a unified form. These integral operators produce various well known integral operators in the theory of fractional calculus. Formulated integral operators of this study include generalized fractional integral operators of Riemann-Liouville type and operators containing Mittag-Leffler functions in their kernels. Also boundedness of all these fractional integral operators is derived from the boundedness of unified integral operators. The existence of new integral operators may have useful consequences in applied sciences besides in fractional calculus.
Positive solutions for boundary value problem of sixth-order elastic beam equation
OMS-Vol. 4 (2020), Issue 1, pp. 9 – 17 Open Access Full-Text PDF
Zouaoui Bekri, Slimane Benaicha
Abstract: In this paper, we study the existence of positive solutions for boundary value problem of sixth-order elastic beam equation of the form \(-u^{(6)}(t)=q(t)f(t,u(t),u^{‘}(t),u^{”}(t),u^{”’}(t),u^{(4)}(t),u^{(5)}(t)),~~0<t<1,\) with conditions \(u(0)=u^{‘}(1)=u^{”}(0)=u^{”’}(1)=u^{(4)}(0)=u^{(5)}(1)=0,\) where \(f\in C([0,1]\times[0,\infty)\times[0,\infty)\times(-\infty,0]\times(-\infty,0]\times[0,\infty)\times[0,\infty)\rightarrow [0,\infty))\). The boundary conditions describe the deformation of an elastic beam simply supported at left and clamped at right by sliding clamps. We give sufficient conditions that allow us to obtain the existence of positive solution. The main tool used in the proof is the Leray-Schauder nonlinear alternative and Leray-Schauder fixed point theorem. As an application, we also give example to illustrate the results obtained.