Pub Date : 2025-10-24DOI: 10.1016/j.na.2025.113983
Nicolas Beuvin, Alberto Farina
We prove new one-dimensional symmetry results for non-negative solutions, possibly unbounded, to the semilinear equation in the upper half-space . Some Liouville-type theorems are also proven in the case of differential inequalities in , even without imposing any boundary condition.
Although subject to dimensional restrictions, our results apply to a broad family of functions . In particular, they apply to all non-negative that behaves at least linearly at infinity.
{"title":"One-dimensional symmetry results for semilinear equations and inequalities on half-spaces","authors":"Nicolas Beuvin, Alberto Farina","doi":"10.1016/j.na.2025.113983","DOIUrl":"10.1016/j.na.2025.113983","url":null,"abstract":"<div><div>We prove new one-dimensional symmetry results for non-negative solutions, possibly unbounded, to the semilinear equation <span><math><mrow><mo>−</mo><mi>Δ</mi><mi>u</mi><mo>=</mo><mi>f</mi><mrow><mo>(</mo><mi>u</mi><mo>)</mo></mrow></mrow></math></span> in the upper half-space <span><math><msubsup><mrow><mi>R</mi></mrow><mrow><mo>+</mo></mrow><mrow><mi>N</mi></mrow></msubsup></math></span>. Some Liouville-type theorems are also proven in the case of differential inequalities in <span><math><msubsup><mrow><mi>R</mi></mrow><mrow><mo>+</mo></mrow><mrow><mi>N</mi></mrow></msubsup></math></span>, even without imposing any boundary condition.</div><div>Although subject to dimensional restrictions, our results apply to a broad family of functions <span><math><mi>f</mi></math></span>. In particular, they apply to all non-negative <span><math><mi>f</mi></math></span> that behaves at least linearly at infinity.</div></div>","PeriodicalId":49749,"journal":{"name":"Nonlinear Analysis-Theory Methods & Applications","volume":"264 ","pages":"Article 113983"},"PeriodicalIF":1.3,"publicationDate":"2025-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145340633","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-24DOI: 10.1016/j.na.2025.113984
Wojciech Górny , Michał Łasica , Alexandros Matsoukas
We consider a class of integral functionals with Musielak–Orlicz type variable growth, possibly linear in some regions of the domain. This includes power-type integrands with as well as double-phase integrands with . The main goal of this paper is to identify the -subdifferential of the functional, including a local characterisation in terms of a variant of the Anzellotti product defined through the Young’s inequality. As an application, we obtain the Euler–Lagrange equation for the variant of Rudin–Osher–Fatemi image denoising problem with variable growth regularising term. Moreover, we provide a characterisation of the -gradient flow of variable-growth total variation in terms of a parabolic PDE.
{"title":"Euler–Lagrange equations for variable-growth total variation","authors":"Wojciech Górny , Michał Łasica , Alexandros Matsoukas","doi":"10.1016/j.na.2025.113984","DOIUrl":"10.1016/j.na.2025.113984","url":null,"abstract":"<div><div>We consider a class of integral functionals with Musielak–Orlicz type variable growth, possibly linear in some regions of the domain. This includes <span><math><mrow><mi>p</mi><mrow><mo>(</mo><mi>x</mi><mo>)</mo></mrow></mrow></math></span> power-type integrands with <span><math><mrow><mi>p</mi><mrow><mo>(</mo><mi>x</mi><mo>)</mo></mrow><mo>≥</mo><mn>1</mn></mrow></math></span> as well as double-phase <span><math><mrow><mi>p</mi><mspace></mspace><mo>−</mo><mspace></mspace><mi>q</mi></mrow></math></span> integrands with <span><math><mrow><mi>p</mi><mo>=</mo><mn>1</mn></mrow></math></span>. The main goal of this paper is to identify the <span><math><msup><mrow><mi>L</mi></mrow><mrow><mn>2</mn></mrow></msup></math></span>-subdifferential of the functional, including a local characterisation in terms of a variant of the Anzellotti product defined through the Young’s inequality. As an application, we obtain the Euler–Lagrange equation for the variant of Rudin–Osher–Fatemi image denoising problem with variable growth regularising term. Moreover, we provide a characterisation of the <span><math><msup><mrow><mi>L</mi></mrow><mrow><mn>2</mn></mrow></msup></math></span>-gradient flow of variable-growth total variation in terms of a parabolic PDE.</div></div>","PeriodicalId":49749,"journal":{"name":"Nonlinear Analysis-Theory Methods & Applications","volume":"263 ","pages":"Article 113984"},"PeriodicalIF":1.3,"publicationDate":"2025-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145364205","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-24DOI: 10.1016/j.na.2025.113968
Ruhua Zhang , Guanggui Chen
In this paper, we establish the Hörmander type multiplier theorem for Fourier multipliers on Hardy spaces for , with regularity condition formulated in terms of modulation spaces where . We further investigate the boundedness of Fourier multipliers on Lebesgue spaces for through the interpolation. The conditions proposed in this paper not only improve those established by previous researchers but also refine the corresponding conclusions. Additionally, we introduce a novel multiplier theorem that incorporates the regularity condition formulated in terms of Wiener amalgam spaces . Here the multiplier theorem may be of methodology to further studies of Fourier multipliers.
{"title":"On the boundedness of Fourier multipliers in terms of modulation spaces regularity","authors":"Ruhua Zhang , Guanggui Chen","doi":"10.1016/j.na.2025.113968","DOIUrl":"10.1016/j.na.2025.113968","url":null,"abstract":"<div><div>In this paper, we establish the Hörmander type multiplier theorem for Fourier multipliers on Hardy spaces <span><math><mrow><msup><mrow><mi>H</mi></mrow><mrow><mi>p</mi></mrow></msup><mfenced><mrow><msup><mrow><mi>R</mi></mrow><mrow><mi>n</mi></mrow></msup></mrow></mfenced></mrow></math></span> for <span><math><mrow><mn>0</mn><mo><</mo><mi>p</mi><mo>≤</mo><mn>1</mn></mrow></math></span>, with regularity condition formulated in terms of modulation spaces <span><math><mrow><msubsup><mrow><mi>M</mi></mrow><mrow><mi>s</mi></mrow><mrow><mi>r</mi><mo>,</mo><mi>q</mi></mrow></msubsup><mfenced><mrow><msup><mrow><mi>R</mi></mrow><mrow><mi>n</mi></mrow></msup></mrow></mfenced></mrow></math></span> where <span><math><mrow><mn>1</mn><mo>≤</mo><mi>r</mi><mo>,</mo><mi>q</mi><mo>≤</mo><mi>∞</mi><mo>,</mo><mi>s</mi><mo>></mo><mfrac><mrow><mi>n</mi></mrow><mrow><mi>p</mi></mrow></mfrac><mo>−</mo><mfrac><mrow><mi>n</mi></mrow><mrow><mi>q</mi></mrow></mfrac></mrow></math></span>. We further investigate the boundedness of Fourier multipliers on Lebesgue spaces <span><math><mrow><msup><mrow><mi>L</mi></mrow><mrow><mi>p</mi></mrow></msup><mfenced><mrow><msup><mrow><mi>R</mi></mrow><mrow><mi>n</mi></mrow></msup></mrow></mfenced></mrow></math></span> for <span><math><mrow><mn>1</mn><mo><</mo><mi>p</mi><mo><</mo><mi>∞</mi></mrow></math></span> through the interpolation. The conditions proposed in this paper not only improve those established by previous researchers but also refine the corresponding conclusions. Additionally, we introduce a novel multiplier theorem that incorporates the regularity condition formulated in terms of Wiener amalgam spaces <span><math><mrow><msubsup><mrow><mi>W</mi></mrow><mrow><mi>s</mi></mrow><mrow><mi>r</mi><mo>,</mo><mi>q</mi></mrow></msubsup><mfenced><mrow><msup><mrow><mi>R</mi></mrow><mrow><mi>n</mi></mrow></msup></mrow></mfenced></mrow></math></span>. Here the multiplier theorem may be of methodology to further studies of Fourier multipliers.</div></div>","PeriodicalId":49749,"journal":{"name":"Nonlinear Analysis-Theory Methods & Applications","volume":"263 ","pages":"Article 113968"},"PeriodicalIF":1.3,"publicationDate":"2025-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145364204","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-23DOI: 10.1016/j.na.2025.113987
Francesca Da Lio, Tristan Rivière, Dominik Schlagenhauf
In this paper we consider sequences of -harmonic maps, , from a closed Riemann surface into the -dimensional sphere with uniform bounded energy. These are critical points of the energy Our two main results are an improved pointwise estimate of the gradient in the neck regions around blow up points and the proof that the necks are asymptotically not contributing to the negativity of the second variation of the energy This allows us, in the spirit of the paper of the first and second authors in collaboration with Gianocca et al. (2022) , to show the upper semicontinuity of the Morse index plus nullity for sequences of -harmonic maps into a sphere.
{"title":"Morse index stability for Sacks–Uhlenbeck approximations for harmonic maps into a sphere","authors":"Francesca Da Lio, Tristan Rivière, Dominik Schlagenhauf","doi":"10.1016/j.na.2025.113987","DOIUrl":"10.1016/j.na.2025.113987","url":null,"abstract":"<div><div>In this paper we consider sequences of <span><math><mi>p</mi></math></span>-harmonic maps, <span><math><mrow><mi>p</mi><mo>></mo><mn>2</mn></mrow></math></span>, from a closed Riemann surface <span><math><mi>Σ</mi></math></span> into the <span><math><mi>n</mi></math></span>-dimensional sphere <span><math><msup><mrow><mi>S</mi></mrow><mrow><mi>n</mi></mrow></msup></math></span> with uniform bounded energy. These are critical points of the energy <span><math><mrow><msub><mrow><mi>E</mi></mrow><mrow><mi>p</mi></mrow></msub><mrow><mo>(</mo><mi>u</mi><mo>)</mo></mrow><mo>≔</mo><msub><mrow><mo>∫</mo></mrow><mrow><mi>Σ</mi></mrow></msub><msup><mrow><mfenced><mrow><mn>1</mn><mo>+</mo><msup><mrow><mrow><mo>|</mo><mo>∇</mo><mi>u</mi><mo>|</mo></mrow></mrow><mrow><mn>2</mn></mrow></msup></mrow></mfenced></mrow><mrow><mi>p</mi><mo>/</mo><mn>2</mn></mrow></msup><mspace></mspace><mi>d</mi><mi>v</mi><mi>o</mi><msub><mrow><mi>l</mi></mrow><mrow><mi>Σ</mi></mrow></msub><mo>.</mo></mrow></math></span> Our two main results are an improved pointwise estimate of the gradient in the neck regions around blow up points and the proof that the necks are asymptotically not contributing to the negativity of the second variation of the energy <span><math><mrow><msub><mrow><mi>E</mi></mrow><mrow><mi>p</mi></mrow></msub><mo>.</mo></mrow></math></span> This allows us, in the spirit of the paper of the first and second authors in collaboration with Gianocca et al. (2022) , to show the upper semicontinuity of the Morse index plus nullity for sequences of <span><math><mi>p</mi></math></span>-harmonic maps into a sphere.</div></div>","PeriodicalId":49749,"journal":{"name":"Nonlinear Analysis-Theory Methods & Applications","volume":"264 ","pages":"Article 113987"},"PeriodicalIF":1.3,"publicationDate":"2025-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145340632","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-21DOI: 10.1016/j.na.2025.113980
Ze-Yu Ye, Xiao-Liu Wang
In this paper, we study a generalized gradient flow of anisoperimetric ratio, whose inner normal velocity contains a power of anisotropic curvature for convex closed curves. It is shown that for any embedded smooth closed convex initial curve, the flow exists globally and the curvature of evolving curves converges smoothly to the curvature of the boundary of the Wulff shape, which is determined by the given anisotropic function, as time goes to infinity.
{"title":"Evolution of convex closed curves under the generalized gradient flow of anisoperimetric ratio","authors":"Ze-Yu Ye, Xiao-Liu Wang","doi":"10.1016/j.na.2025.113980","DOIUrl":"10.1016/j.na.2025.113980","url":null,"abstract":"<div><div>In this paper, we study a generalized gradient flow of anisoperimetric ratio, whose inner normal velocity contains a power of anisotropic curvature for convex closed curves. It is shown that for any embedded smooth closed convex initial curve, the flow exists globally and the curvature of evolving curves converges smoothly to the curvature of the boundary of the Wulff shape, which is determined by the given anisotropic function, as time goes to infinity.</div></div>","PeriodicalId":49749,"journal":{"name":"Nonlinear Analysis-Theory Methods & Applications","volume":"263 ","pages":"Article 113980"},"PeriodicalIF":1.3,"publicationDate":"2025-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145363696","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-15DOI: 10.1016/j.na.2025.113979
Matteo Muratori , Troy Petitt , Fernando Quirós
We investigate the asymptotic behavior as of solutions to a weighted porous medium equation in , whose weight behaves at spatial infinity like with subcritical power, namely . Inspired by some results (Alikakos and Rostamian, 1984; Kamin and Ughi, 1987) from the 1980s on the unweighted problem, we focus on solutions whose initial data are not globally integrable with respect to the weight and behave at infinity like , for . In the special case and we show that self-similar solutions of Barenblatt type, i.e. reminiscent of the usual source-type solutions, still exist, although they are no longer compactly supported. Moreover, they exhibit a transition phenomenon which is new even for the unweighted equation. We prove that such self-similar solutions are attractors for the original problem, and convergence takes place globally in suitable weighted spaces for and even globally in under some mild additional regularity assumptions on the weight. Among the fundamental tools that we exploit, it is worth mentioning a global smoothing effect for non-integrable data.
{"title":"An inhomogeneous porous medium equation with non-integrable data: Asymptotics","authors":"Matteo Muratori , Troy Petitt , Fernando Quirós","doi":"10.1016/j.na.2025.113979","DOIUrl":"10.1016/j.na.2025.113979","url":null,"abstract":"<div><div>We investigate the asymptotic behavior as <span><math><mrow><mi>t</mi><mo>→</mo><mo>+</mo><mi>∞</mi></mrow></math></span> of solutions to a weighted porous medium equation in <span><math><msup><mrow><mi>R</mi></mrow><mrow><mi>N</mi></mrow></msup></math></span>, whose weight <span><math><mrow><mi>ρ</mi><mrow><mo>(</mo><mi>x</mi><mo>)</mo></mrow></mrow></math></span> behaves at spatial infinity like <span><math><msup><mrow><mrow><mo>|</mo><mi>x</mi><mo>|</mo></mrow></mrow><mrow><mo>−</mo><mi>γ</mi></mrow></msup></math></span> with subcritical power, namely <span><math><mrow><mi>γ</mi><mo>∈</mo><mrow><mo>[</mo><mn>0</mn><mo>,</mo><mn>2</mn><mo>)</mo></mrow></mrow></math></span>. Inspired by some results (Alikakos and Rostamian, 1984; Kamin and Ughi, 1987) from the 1980s on the unweighted problem, we focus on solutions whose initial data <span><math><mrow><msub><mrow><mi>u</mi></mrow><mrow><mn>0</mn></mrow></msub><mrow><mo>(</mo><mi>x</mi><mo>)</mo></mrow></mrow></math></span> are not globally integrable with respect to the weight and behave at infinity like <span><math><msup><mrow><mrow><mo>|</mo><mi>x</mi><mo>|</mo></mrow></mrow><mrow><mo>−</mo><mi>α</mi></mrow></msup></math></span>, for <span><math><mrow><mi>α</mi><mo>∈</mo><mrow><mo>(</mo><mn>0</mn><mo>,</mo><mi>N</mi><mo>−</mo><mi>γ</mi><mo>)</mo></mrow></mrow></math></span>. In the special case <span><math><mrow><mi>ρ</mi><mrow><mo>(</mo><mi>x</mi><mo>)</mo></mrow><mo>=</mo><msup><mrow><mrow><mo>|</mo><mi>x</mi><mo>|</mo></mrow></mrow><mrow><mo>−</mo><mi>γ</mi></mrow></msup></mrow></math></span> and <span><math><mrow><msub><mrow><mi>u</mi></mrow><mrow><mn>0</mn></mrow></msub><mrow><mo>(</mo><mi>x</mi><mo>)</mo></mrow><mo>=</mo><msup><mrow><mrow><mo>|</mo><mi>x</mi><mo>|</mo></mrow></mrow><mrow><mo>−</mo><mi>α</mi></mrow></msup></mrow></math></span> we show that self-similar solutions of Barenblatt type, i.e. reminiscent of the usual source-type solutions, still exist, although they are no longer compactly supported. Moreover, they exhibit a transition phenomenon which is new even for the unweighted equation. We prove that such self-similar solutions are attractors for the original problem, and convergence takes place globally in suitable weighted <span><math><msup><mrow><mi>L</mi></mrow><mrow><mi>p</mi></mrow></msup></math></span> spaces for <span><math><mrow><mi>p</mi><mo>∈</mo><mrow><mo>[</mo><mn>1</mn><mo>,</mo><mi>∞</mi><mo>)</mo></mrow></mrow></math></span> and even globally in <span><math><msup><mrow><mi>L</mi></mrow><mrow><mi>∞</mi></mrow></msup></math></span> under some mild additional regularity assumptions on the weight. Among the fundamental tools that we exploit, it is worth mentioning a global smoothing effect for non-integrable data.</div></div>","PeriodicalId":49749,"journal":{"name":"Nonlinear Analysis-Theory Methods & Applications","volume":"263 ","pages":"Article 113979"},"PeriodicalIF":1.3,"publicationDate":"2025-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145322044","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-15DOI: 10.1016/j.na.2025.113976
Jarosław Mederski , Jacopo Schino
We look for travelling wave fields satisfying Maxwell’s equations in a nonlinear and cylindrically symmetric medium. We obtain a sequence of solutions with diverging energy consisting of transverse magnetic field modes. In addition, we consider a general nonlinearity, controlled by an N-function.
{"title":"Travelling waves for Maxwell’s equations in nonlinear and symmetric media","authors":"Jarosław Mederski , Jacopo Schino","doi":"10.1016/j.na.2025.113976","DOIUrl":"10.1016/j.na.2025.113976","url":null,"abstract":"<div><div>We look for travelling wave fields <span><span><span><math><mrow><mi>E</mi><mrow><mo>(</mo><mi>x</mi><mo>,</mo><mi>y</mi><mo>,</mo><mi>z</mi><mo>,</mo><mi>t</mi><mo>)</mo></mrow><mo>=</mo><mi>U</mi><mrow><mo>(</mo><mi>x</mi><mo>,</mo><mi>y</mi><mo>)</mo></mrow><mo>cos</mo><mrow><mo>(</mo><mi>k</mi><mi>z</mi><mo>+</mo><mi>ω</mi><mi>t</mi><mo>)</mo></mrow><mo>+</mo><mover><mrow><mi>U</mi></mrow><mrow><mo>˜</mo></mrow></mover><mrow><mo>(</mo><mi>x</mi><mo>,</mo><mi>y</mi><mo>)</mo></mrow><mo>sin</mo><mrow><mo>(</mo><mi>k</mi><mi>z</mi><mo>+</mo><mi>ω</mi><mi>t</mi><mo>)</mo></mrow><mo>,</mo><mrow><mo>(</mo><mi>x</mi><mo>,</mo><mi>y</mi><mo>,</mo><mi>z</mi><mo>)</mo></mrow><mo>∈</mo><msup><mrow><mi>R</mi></mrow><mrow><mn>3</mn></mrow></msup><mo>,</mo><mspace></mspace><mi>t</mi><mo>∈</mo><mi>R</mi><mo>,</mo></mrow></math></span></span></span>satisfying Maxwell’s equations in a nonlinear and cylindrically symmetric medium. We obtain a sequence of solutions with diverging energy consisting of transverse magnetic field modes. In addition, we consider a general nonlinearity, controlled by an <em>N</em>-function.</div></div>","PeriodicalId":49749,"journal":{"name":"Nonlinear Analysis-Theory Methods & Applications","volume":"263 ","pages":"Article 113976"},"PeriodicalIF":1.3,"publicationDate":"2025-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145322045","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-11DOI: 10.1016/j.na.2025.113975
Diego Alonso-Orán , Claudia García , Rafael Granero-Belinchón
In this note, we study the existence of traveling waves of a surface model in a non-newtonian fluid with odd viscosity. The proof relies on nonlinear bifurcation techniques.
本文研究了奇黏度非牛顿流体中表面模型行波的存在性。该证明依赖于非线性分岔技术。
{"title":"Traveling gravity-capillary waves with odd viscosity","authors":"Diego Alonso-Orán , Claudia García , Rafael Granero-Belinchón","doi":"10.1016/j.na.2025.113975","DOIUrl":"10.1016/j.na.2025.113975","url":null,"abstract":"<div><div>In this note, we study the existence of traveling waves of a surface model in a non-newtonian fluid with odd viscosity. The proof relies on nonlinear bifurcation techniques.</div></div>","PeriodicalId":49749,"journal":{"name":"Nonlinear Analysis-Theory Methods & Applications","volume":"263 ","pages":"Article 113975"},"PeriodicalIF":1.3,"publicationDate":"2025-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145269058","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-10DOI: 10.1016/j.na.2025.113947
Patrick Erik Bradley
The transcendent part of the Drinfel’d -adic upper half plane is shown to be a Polish space. Using Radon measures associated with regular differential 1-forms invariant under Schottky groups allows to construct self-adjoint diffusion operators as Laplacian integral operators with kernel functions determined by the -adic absolute value on the complex -adic numbers. Their spectra are explicitly calculated and the corresponding Cauchy problems for their associated heat equations are found to be uniquely solvable and to determine Markov processes having paths which are càdlàg. The heat kernels are shown to have explicitly given distribution functions, as well as boundary value problems associated with the heat equations under Dirichlet and von Neumann conditions are solved.
{"title":"Schottky invariant diffusion on the transcendent p-adic upper half plane","authors":"Patrick Erik Bradley","doi":"10.1016/j.na.2025.113947","DOIUrl":"10.1016/j.na.2025.113947","url":null,"abstract":"<div><div>The transcendent part of the Drinfel’d <span><math><mi>p</mi></math></span>-adic upper half plane is shown to be a Polish space. Using Radon measures associated with regular differential 1-forms invariant under Schottky groups allows to construct self-adjoint diffusion operators as Laplacian integral operators with kernel functions determined by the <span><math><mi>p</mi></math></span>-adic absolute value on the complex <span><math><mi>p</mi></math></span>-adic numbers. Their spectra are explicitly calculated and the corresponding Cauchy problems for their associated heat equations are found to be uniquely solvable and to determine Markov processes having paths which are càdlàg. The heat kernels are shown to have explicitly given distribution functions, as well as boundary value problems associated with the heat equations under Dirichlet and von Neumann conditions are solved.</div></div>","PeriodicalId":49749,"journal":{"name":"Nonlinear Analysis-Theory Methods & Applications","volume":"263 ","pages":"Article 113947"},"PeriodicalIF":1.3,"publicationDate":"2025-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145270070","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-10DOI: 10.1016/j.na.2025.113978
Antonio Arnal
We study the generator of the one-dimensional damped wave equation with unbounded damping at infinity. We show that the norm of the corresponding resolvent operator, , is approximately constant as on vertical strips of bounded width contained in the closure of the left-hand side complex semi-plane, . Our proof rests on a precise asymptotic analysis of the norm of the inverse of , the quadratic operator associated with .
{"title":"Resolvent estimates for the one-dimensional damped wave equation with unbounded damping","authors":"Antonio Arnal","doi":"10.1016/j.na.2025.113978","DOIUrl":"10.1016/j.na.2025.113978","url":null,"abstract":"<div><div>We study the generator <span><math><mi>G</mi></math></span> of the one-dimensional damped wave equation with unbounded damping at infinity. We show that the norm of the corresponding resolvent operator, <span><math><mrow><mo>‖</mo><msup><mrow><mrow><mo>(</mo><mi>G</mi><mo>−</mo><mi>λ</mi><mo>)</mo></mrow></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup><mo>‖</mo></mrow></math></span>, is approximately constant as <span><math><mrow><mrow><mo>|</mo><mi>λ</mi><mo>|</mo></mrow><mo>→</mo><mo>+</mo><mi>∞</mi></mrow></math></span> on vertical strips of bounded width contained in the closure of the left-hand side complex semi-plane, <span><math><mrow><msub><mrow><mover><mrow><mi>ℂ</mi></mrow><mo>¯</mo></mover></mrow><mrow><mo>−</mo></mrow></msub><mo>≔</mo><mrow><mo>{</mo><mi>λ</mi><mo>∈</mo><mi>ℂ</mi><mo>:</mo><mo>Re</mo><mi>λ</mi><mo>≤</mo><mn>0</mn><mo>}</mo></mrow></mrow></math></span>. Our proof rests on a precise asymptotic analysis of the norm of the inverse of <span><math><mrow><mi>T</mi><mrow><mo>(</mo><mi>λ</mi><mo>)</mo></mrow></mrow></math></span>, the quadratic operator associated with <span><math><mi>G</mi></math></span>.</div></div>","PeriodicalId":49749,"journal":{"name":"Nonlinear Analysis-Theory Methods & Applications","volume":"263 ","pages":"Article 113978"},"PeriodicalIF":1.3,"publicationDate":"2025-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145270053","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}