Tamkang Journal of Mathematics https://journals.math.tku.edu.tw/index.php/TKJM <div>To promote research interactions between local and overseas researchers, the Department of Mathematics of Tamkang University has been publishing an international mathematics journal, the Tamkang Journal of Mathematics. The journal started as a biannual journal in 1970 and is devoted to high-quality original research papers in pure and applied mathematics. In 1985 it has become a quarterly journal.</div> Tamkang University en-US Tamkang Journal of Mathematics 0049-2930 On a class of Kirchhoff type problems with singular exponential nonlinearity https://journals.math.tku.edu.tw/index.php/TKJM/article/view/5097 <pre>We study the following singular Kirchhoff type problem </pre> <pre>\[<br>\left( P\right) \left\{</pre> <pre>\begin{array} [c]{c}</pre> <pre>-m\left({\displaystyle\int\limits_{\Omega}}\left\vert \nabla u\right\vert ^{2}dx\right) \Delta u=h\left( u\right)</pre> <pre>\frac{e^{\alpha u^{2}}}{\left\vert x\right\vert ^{\beta}}\text{ \ \ \ in} \Omega,\\</pre> <pre>u=0 \text{on}\; \partial\Omega</pre> <pre>\end{array} \right.</pre> <pre>\]</pre> <pre>where $\Omega\subset\mathbb{R}^{2}$ is a bounded domain with smooth boundary and $0\in\Omega,$ $\beta\in\left[ 0,2\right)$, $\alpha&gt;0$ and $m$ is a continuous function</pre> <pre>on $\mathbb{R}^{+}.$ Here, $h$ is a suitable preturbation of $e^{\alpha u^{2}}$ as $u\rightarrow\infty.$ In this paper, we prove the existence of solutions of</pre> <pre>$(P)$. Our tools are Trudinger-Moser inequality with a singular weight and the mountain pass theorem</pre> Mebarka Sattaf Brahim Khaldi Copyright (c) 2023 Tamkang Journal of Mathematics https://creativecommons.org/licenses/by-nc-sa/4.0 2023-04-26 2023-04-26 55 2 97 111 10.5556/j.tkjm.55.2024.5097 The evolution of the electric field along optical fiber with respect to the type-2 and 3 PAFs in Minkowski 3-space https://journals.math.tku.edu.tw/index.php/TKJM/article/view/5028 <p>In this paper, we introduce the type-2 and the type-3 Positional Adapted Frame(PAF) of spacelike curve and timelike curve in<br>Minkowski 3-space. From these PAFs, we study the evolutions of the electric field vectors of the type-2 and type-3 PAFs.<br>As a result, we also investigate the Fermi-Walker parallel and the Lorentz force equation of the electric field vectors for the type-2 and type-3 PAFs in Minkowski 3-space.</p> Nevin Ertu\u{g} G\"{u}rb\"{u}z Dae Won Yoon Copyright (c) 2023 Tamkang Journal of Mathematics https://creativecommons.org/licenses/by-nc-sa/4.0 2023-04-28 2023-04-28 55 2 113 128 10.5556/j.tkjm.55.2024.5028 Fixed point theorems with PPF dependence in strong partial b-metric spaces https://journals.math.tku.edu.tw/index.php/TKJM/article/view/5079 <pre>In this study, PPF dependent fixed point theorems are proved for a nonlinear operator, where the domain space $C[[a, b], E]$ is distinct from the range space, $E$, which is a Strong Partial b-metric space (SPbMS). We obtain existence and uniqueness of PPF dependent fixed point results for the defined mappings under SPbMS. Our results are the extension of fixed point results in SPbMS. Examples are provided in the support of results.</pre> Savita Rathee Monika Swami Neelam Kumari Copyright (c) 2023 Tamkang Journal of Mathematics https://creativecommons.org/licenses/by-nc-sa/4.0 2023-05-03 2023-05-03 55 2 129 147 10.5556/j.tkjm.55.2024.5079 A study of statistical submersions https://journals.math.tku.edu.tw/index.php/TKJM/article/view/5044 <p>In the sixties, A. Gray \cite{Gr} and B. O'Neill \cite{O1} come with the notion of Riemannian submersions as a tool to study the geometry of a Riemannian manifold with an additional structure in terms of the fibers and the base space. Riemannian submersions have long been an effective tool to construct Riemannian manifolds with positive or nonnegative sectional curvature in Riemannian geometry and compare certain manifolds within differential geometry. In particular, many examples of Einstein manifolds can be constructed by using such submersions. It is very well known that Riemannian submersions have applications in physics, for example Kaluza-Klein theory, Yang-Mills theory, supergravity and superstring theories.</p> Aliya Naaz Siddiqui Kamran Ahmad Copyright (c) 2023 Tamkang Journal of Mathematics https://creativecommons.org/licenses/by-nc-sa/4.0 2023-05-17 2023-05-17 55 2 149 178 10.5556/j.tkjm.55.2024.5044 A unique continuation result for a system of nonlinear differential equations https://journals.math.tku.edu.tw/index.php/TKJM/article/view/5126 <p>Using an appropriate Carleman-type estimate, we establish a result of unique continuation for a special class of one-dimensional systems that model the evolution of long water waves with small amplitude in the presence of surface tension.</p> Alex M Montes Ricardo Córdoba Copyright (c) 2023 Tamkang Journal of Mathematics https://creativecommons.org/licenses/by-nc-sa/4.0 2023-05-22 2023-05-22 55 2 179 193 10.5556/j.tkjm.55.2024.5126 On the numerical radius of an upper triangular operator matrix https://journals.math.tku.edu.tw/index.php/TKJM/article/view/5094 <p>The main purpose of this paper is to give an improvement of numerical radius inequality for an upper triangular operator matrix.</p> Mehdi Naimi Mohammed Benharrat Copyright (c) 2023 Tamkang Journal of Mathematics https://creativecommons.org/licenses/by-nc-sa/4.0 2023-07-05 2023-07-05 55 2 195 201 10.5556/j.tkjm.55.2024.5094