{"title":"Observer-Based Boundary Control for Coupled Parabolic PDEs With Spatially Varying Coefficients","authors":"Seyedamin Hatami, Mohammad Keyanpour","doi":"10.1002/mma.70943","DOIUrl":"https://doi.org/10.1002/mma.70943","url":null,"abstract":"<div>\u0000 \u0000 <p>This paper addresses the observer-based output-feedback boundary control design for a system of <span></span><math>\u0000 <mrow>\u0000 <mi>n</mi>\u0000 </mrow></math>-coupled parabolic partial differential equations (PDEs) with spatially varying diffusion coefficients without any ordering conditions. First, a boundary observer is proposed to estimate the system states, with its gain determined by considering a stable target system and using a backstepping transformation method. To design an observer-based boundary controller for <span></span><math>\u0000 <mrow>\u0000 <mi>n</mi>\u0000 </mrow></math>-coupled parabolic PDE systems, we construct a backstepping transformation that maps the observer dynamics into a stable target system, yielding the associated kernel and boundary control law, which is the main contribution of this work. Furthermore, analytical solutions to two sets of kernel equations are derived to determine the controller and observer gains. By employing Lyapunov stability analysis, we prove that the proposed output-feedback architecture guarantees exponential stability of the entire closed-loop system. Finally, numerical simulations are conducted to validate the theoretical results of the proposed method.</p>\u0000 </div>","PeriodicalId":49865,"journal":{"name":"Mathematical Methods in the Applied Sciences","volume":"49 17","pages":"17933-17951"},"PeriodicalIF":2.0,"publicationDate":"2026-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149311603","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Space-Time Spectral Element Method for PIDEs Arising in Finance","authors":"Zhiyuan Hui, Xuchen Jin, Changtao Sheng","doi":"10.1002/mma.70948","DOIUrl":"https://doi.org/10.1002/mma.70948","url":null,"abstract":"<div>\u0000 \u0000 <p>This paper proposes an efficient space-time spectral element method for option pricing under the Merton jump-diffusion model. The model gives rise to a partial integro-differential equation (PIDE) with a nonlocal integral term and temporal singularities due to nonsmooth initial data. To resolve these singularities and ensure high-order accuracy, we employ an <span></span><math>\u0000 <mrow>\u0000 <mi>h</mi>\u0000 <mi>p</mi>\u0000 </mrow></math>-version of continuous Galerkin scheme with graded time steps. For the spatial discretization, we employ a Laguerre–Legendre composite spectral element method on unbounded domains, which attains spectral accuracy with relatively few degrees of freedom for solutions with slope discontinuities. The resulting space-time discretization gives rise to highly ill-conditioned and nonsymmetric linear systems. To address this difficulty, we design a stable and efficient solver based on QZ decomposition and demonstrate its superiority over tensor-product direct solvers and eigenvalue decomposition methods. Numerical experiments confirm the predicted spectral convergence and highlight the accuracy and efficiency of the proposed method in comparison with existing approaches.</p>\u0000 </div>","PeriodicalId":49865,"journal":{"name":"Mathematical Methods in the Applied Sciences","volume":"49 17","pages":"17739-17762"},"PeriodicalIF":2.0,"publicationDate":"2026-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149312360","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"On the Global Asymptotic Stability of an Infection-Age-Structured Competitive Model","authors":"S. Girel, Q. Richard","doi":"10.1002/mma.70967","DOIUrl":"https://doi.org/10.1002/mma.70967","url":null,"abstract":"<p>We investigate an infection-age-structured competitive epidemiological model involving multiple strains. While classical results establish competitive exclusion when a unique maximal basic reproduction number exists, we provide here a complete characterization of the asymptotic behavior for an arbitrary number of populations without assuming uniqueness of the maximal reproduction number. By means of integrated semigroups theory, persistence results, and Lyapunov functionals, we establish global asymptotic stability of equilibria and extend previous results obtained for simpler (ODE) models. A key contribution lies in overcoming technical difficulties related to the definition and differentiation of Lyapunov functionals, as well as in refining arguments based on the LaSalle invariance principle.</p>","PeriodicalId":49865,"journal":{"name":"Mathematical Methods in the Applied Sciences","volume":"49 17","pages":"18040-18072"},"PeriodicalIF":2.0,"publicationDate":"2026-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/mma.70967","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149311939","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"New Hermite–Hadamard Type Bounds for Co-ordinated Convex Functions via Non-Conformable Fractional Integrals","authors":"Arslan Razzaq, Zhouchao Wei","doi":"10.1002/mma.70968","DOIUrl":"https://doi.org/10.1002/mma.70968","url":null,"abstract":"<div>\u0000 \u0000 <p>In this paper, we establish two new identities for functions of two variables and use them to provide new Hermite–Hadamard (H-H)-type fractional integral inequalities for double non-conformable fractional integrals operators whose derivatives are bounded or co-ordinate convex functions on <span></span><math>\u0000 <mrow>\u0000 <mi>Θ</mi>\u0000 <mo>:</mo>\u0000 <mo>=</mo>\u0000 <mo>[</mo>\u0000 <mi>ζ</mi>\u0000 <mo>,</mo>\u0000 <mi>η</mi>\u0000 <mo>]</mo>\u0000 <mo>×</mo>\u0000 <mo>[</mo>\u0000 <mi>ς</mi>\u0000 <mo>,</mo>\u0000 <mi>ϑ</mi>\u0000 <mo>]</mo>\u0000 </mrow></math> in <span></span><math>\u0000 <mrow>\u0000 <msup>\u0000 <mrow>\u0000 <mi>ℝ</mi>\u0000 </mrow>\u0000 <mrow>\u0000 <mn>2</mn>\u0000 </mrow>\u0000 </msup>\u0000 </mrow></math> with <span></span><math>\u0000 <mrow>\u0000 <mi>ζ</mi>\u0000 <mo><</mo>\u0000 <mi>η</mi>\u0000 </mrow></math> and <span></span><math>\u0000 <mrow>\u0000 <mi>ς</mi>\u0000 <mo><</mo>\u0000 <mi>ϑ</mi>\u0000 </mrow></math>.</p>\u0000 </div>","PeriodicalId":49865,"journal":{"name":"Mathematical Methods in the Applied Sciences","volume":"49 17","pages":"17983-17998"},"PeriodicalIF":2.0,"publicationDate":"2026-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149311741","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Leighton–Wintner-Type Oscillation Criteria for the \u0000 \u0000 p\u0000 (\u0000 t\u0000 )\u0000 -Laplacian Dynamic Equations on Time Scales","authors":"Kōdai Fujimoto, Kazuki Ishibashi, Masakazu Onitsuka","doi":"10.1002/mma.70941","DOIUrl":"https://doi.org/10.1002/mma.70941","url":null,"abstract":"<p>This study investigates oscillation problems for <span></span><math>\u0000 <mrow>\u0000 <mi>p</mi>\u0000 <mo>(</mo>\u0000 <mi>t</mi>\u0000 <mo>)</mo>\u0000 </mrow></math>-Laplacian dynamic equations on time scales. By employing the Riccati transformation technique, we establish a new Leighton–Wintner-type oscillation theorem for the equations under consideration, which unifies and extends existing results for both differential and difference equations. As illustrative examples, we present several equations, including differential equations on <span></span><math>\u0000 <mrow>\u0000 <mi>ℝ</mi>\u0000 </mrow></math>, difference equations on <span></span><math>\u0000 <mrow>\u0000 <mi>ℕ</mi>\u0000 </mrow></math>, equations on hybrid time scales combining continuous and discrete parts, and <span></span><math>\u0000 <mrow>\u0000 <mi>q</mi>\u0000 </mrow></math>-difference equations, and show that all proper solutions are oscillatory. The effectiveness of the obtained results is confirmed through numerical simulations.</p>","PeriodicalId":49865,"journal":{"name":"Mathematical Methods in the Applied Sciences","volume":"49 17","pages":"17617-17626"},"PeriodicalIF":2.0,"publicationDate":"2026-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/mma.70941","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149312021","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}