Pub Date : 2026-01-28DOI: 10.1016/j.jde.2026.114135
Simone Mauro , Delia Schiera , Hugo Tavares
We study the following gradient elliptic system with Neumann boundary conditions where is a bounded domain with , and ν denotes the outward unit normal on the boundary. We investigate the existence of non-constant least energy solutions in both the cooperative () and the competitive () regimes, considering both the definite and the indefinite case, namely . We emphasize that our analysis includes both the subcritical case and the critical case .
Depending on the values of , the least energy solution is obtained either via a linking theorem, by minimizing over a suitable Nehari manifold, or by direct minimization on the set of all non-trivial weak solutions. Our results and techniques can be also adapted to cover some previously untreated cases for Dirichlet conditions.
{"title":"Least energy solutions for cooperative and competitive Schrödinger systems with Neumann boundary conditions","authors":"Simone Mauro , Delia Schiera , Hugo Tavares","doi":"10.1016/j.jde.2026.114135","DOIUrl":"10.1016/j.jde.2026.114135","url":null,"abstract":"<div><div>We study the following gradient elliptic system with Neumann boundary conditions<span><span><span><math><mo>−</mo><mi>Δ</mi><mi>u</mi><mo>+</mo><msub><mrow><mi>λ</mi></mrow><mrow><mn>1</mn></mrow></msub><mi>u</mi><mo>=</mo><msup><mrow><mi>u</mi></mrow><mrow><mn>3</mn></mrow></msup><mo>+</mo><mi>β</mi><mi>u</mi><msup><mrow><mi>v</mi></mrow><mrow><mn>2</mn></mrow></msup><mo>,</mo><mspace></mspace><mo>−</mo><mi>Δ</mi><mi>v</mi><mo>+</mo><msub><mrow><mi>λ</mi></mrow><mrow><mn>2</mn></mrow></msub><mi>v</mi><mo>=</mo><msup><mrow><mi>v</mi></mrow><mrow><mn>3</mn></mrow></msup><mo>+</mo><mi>β</mi><msup><mrow><mi>u</mi></mrow><mrow><mn>2</mn></mrow></msup><mi>v</mi><mspace></mspace><mtext>in </mtext><mi>Ω</mi><mo>,</mo><mspace></mspace><mfrac><mrow><mo>∂</mo><mi>u</mi></mrow><mrow><mo>∂</mo><mi>ν</mi></mrow></mfrac><mo>=</mo><mfrac><mrow><mo>∂</mo><mi>v</mi></mrow><mrow><mo>∂</mo><mi>ν</mi></mrow></mfrac><mo>=</mo><mn>0</mn><mspace></mspace><mtext>on </mtext><mo>∂</mo><mi>Ω</mi><mo>,</mo></math></span></span></span> where <span><math><mi>Ω</mi><mo>⊂</mo><msup><mrow><mi>R</mi></mrow><mrow><mi>N</mi></mrow></msup></math></span> is a bounded <span><math><msup><mrow><mi>C</mi></mrow><mrow><mn>2</mn></mrow></msup></math></span> domain with <span><math><mi>N</mi><mo>≤</mo><mn>4</mn></math></span>, and <em>ν</em> denotes the outward unit normal on the boundary. We investigate the existence of non-constant least energy solutions in both the cooperative (<span><math><mi>β</mi><mo>></mo><mn>0</mn></math></span>) and the competitive (<span><math><mi>β</mi><mo><</mo><mn>0</mn></math></span>) regimes, considering both the definite and the indefinite case, namely <span><math><msub><mrow><mi>λ</mi></mrow><mrow><mn>1</mn></mrow></msub><mo>,</mo><msub><mrow><mi>λ</mi></mrow><mrow><mn>2</mn></mrow></msub><mo>∈</mo><mi>R</mi></math></span>. We emphasize that our analysis includes both the subcritical case <span><math><mi>N</mi><mo>≤</mo><mn>3</mn></math></span> and the critical case <span><math><mi>N</mi><mo>=</mo><mn>4</mn></math></span>.</div><div>Depending on the values of <span><math><mi>β</mi><mo>,</mo><msub><mrow><mi>λ</mi></mrow><mrow><mn>1</mn></mrow></msub><mo>,</mo><msub><mrow><mi>λ</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span>, the least energy solution is obtained either via a linking theorem, by minimizing over a suitable Nehari manifold, or by direct minimization on the set of all non-trivial weak solutions. Our results and techniques can be also adapted to cover some previously untreated cases for Dirichlet conditions.</div></div>","PeriodicalId":15623,"journal":{"name":"Journal of Differential Equations","volume":"459 ","pages":"Article 114135"},"PeriodicalIF":2.3,"publicationDate":"2026-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146074032","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 : 2026-01-28DOI: 10.1016/j.jde.2026.114142
Jie Chen , Fan Gu , Boling Guo
In this paper, we consider the well-posedness of stochastic S-KdV driven by multiplicative noises in . To get the local well-posedness, we first develop the bilinear and trilinear Bourgain norm estimates of the nonlinear terms with . Then, to overcome regularity problems, we introduce a series of approximation equations with localized nonlinear terms, which are also cutted-off in both the physical and the frequency space. By limitations, these approximation equations will help us get a priori estimate in the Bourgain space and finish the proof of the global well-posedness of the initial system.
{"title":"Stochastic Schrödinger-Korteweg de Vries systems driven by multiplicative noises","authors":"Jie Chen , Fan Gu , Boling Guo","doi":"10.1016/j.jde.2026.114142","DOIUrl":"10.1016/j.jde.2026.114142","url":null,"abstract":"<div><div>In this paper, we consider the well-posedness of stochastic S-KdV driven by multiplicative noises in <span><math><msubsup><mrow><mi>H</mi></mrow><mrow><mi>x</mi></mrow><mrow><mn>1</mn></mrow></msubsup><mo>×</mo><msubsup><mrow><mi>H</mi></mrow><mrow><mi>x</mi></mrow><mrow><mn>1</mn></mrow></msubsup></math></span>. To get the local well-posedness, we first develop the bilinear and trilinear Bourgain norm estimates of the nonlinear terms with <span><math><mi>b</mi><mo>∈</mo><mrow><mo>(</mo><mn>0</mn><mo>,</mo><mn>1</mn><mo>/</mo><mn>2</mn><mo>)</mo></mrow></math></span>. Then, to overcome regularity problems, we introduce a series of approximation equations with localized nonlinear terms, which are also cutted-off in both the physical and the frequency space. By limitations, these approximation equations will help us get a priori estimate in the Bourgain space and finish the proof of the global well-posedness of the initial system.</div></div>","PeriodicalId":15623,"journal":{"name":"Journal of Differential Equations","volume":"461 ","pages":"Article 114142"},"PeriodicalIF":2.3,"publicationDate":"2026-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146074310","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 : 2026-01-28DOI: 10.1016/j.jde.2026.114146
Francesca De Marchis, Lisa Mazzuoli, Filomena Pacella
We consider positive one-dimensional solutions of a Lane-Emden relative Dirichlet problem in a cylinder and study their stability/instability properties as the energy varies with respect to domain perturbations. This depends on the exponent of the nonlinearity and we obtain results for p close to 1 and for p large. This is achieved by a careful asymptotic analysis of the one-dimensional solution as or , which is of independent interest. It allows to detect the limit profile and other qualitative properties of these solutions.
{"title":"Stability and asymptotic behavior of one-dimensional solutions in cylinders","authors":"Francesca De Marchis, Lisa Mazzuoli, Filomena Pacella","doi":"10.1016/j.jde.2026.114146","DOIUrl":"10.1016/j.jde.2026.114146","url":null,"abstract":"<div><div>We consider positive one-dimensional solutions of a Lane-Emden relative Dirichlet problem in a cylinder and study their stability/instability properties as the energy varies with respect to domain perturbations. This depends on the exponent <span><math><mi>p</mi><mo>></mo><mn>1</mn></math></span> of the nonlinearity and we obtain results for <em>p</em> close to 1 and for <em>p</em> large. This is achieved by a careful asymptotic analysis of the one-dimensional solution as <span><math><mi>p</mi><mo>→</mo><mn>1</mn></math></span> or <span><math><mi>p</mi><mo>→</mo><mo>∞</mo></math></span>, which is of independent interest. It allows to detect the limit profile and other qualitative properties of these solutions.</div></div>","PeriodicalId":15623,"journal":{"name":"Journal of Differential Equations","volume":"462 ","pages":"Article 114146"},"PeriodicalIF":2.3,"publicationDate":"2026-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146075452","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 : 2026-01-28DOI: 10.1016/j.jde.2026.114144
Xiandong Lin , Hailong Ye , Xiao-Qiang Zhao
We propose a class of nonlocal dispersal systems on time-varying domains, and fully characterize their asymptotic dynamics in the asymptotically fixed, time-periodic and unbounded cases. We first establish the comparison principle for generalized sub- and supersolutions of a class of nonautonomous nonlocal dispersal systems defined on the space of bounded measurable functions. Based on this, we develop a comprehensive framework to rigorously examine the threshold dynamics of the original system on asymptotically fixed and time-periodic domains. In the asymptotically unbounded case, we introduce a key auxiliary function to address the difficulties caused by the vanishing viscosity as , and the time-dependent coupling structure in the nonlocal kernels. This enables us to construct generalized subsolutions and derive the global threshold dynamics via the comparison principle. The findings may be of independent interest and the developed techniques are expected to find further applications in the related nonlocal dispersal problems. We also conduct numerical simulations for a practical model to illustrate our analytical results.
{"title":"Global dynamics of nonlocal dispersal systems on time-varying domains","authors":"Xiandong Lin , Hailong Ye , Xiao-Qiang Zhao","doi":"10.1016/j.jde.2026.114144","DOIUrl":"10.1016/j.jde.2026.114144","url":null,"abstract":"<div><div>We propose a class of nonlocal dispersal systems on time-varying domains, and fully characterize their asymptotic dynamics in the asymptotically fixed, time-periodic and unbounded cases. We first establish the comparison principle for generalized sub- and supersolutions of a class of nonautonomous nonlocal dispersal systems defined on the space of bounded measurable functions. Based on this, we develop a comprehensive framework to rigorously examine the threshold dynamics of the original system on asymptotically fixed and time-periodic domains. In the asymptotically unbounded case, we introduce a key auxiliary function to address the difficulties caused by the vanishing viscosity as <span><math><mi>t</mi><mo>→</mo><mo>∞</mo></math></span>, and the time-dependent coupling structure in the nonlocal kernels. This enables us to construct generalized subsolutions and derive the global threshold dynamics via the comparison principle. The findings may be of independent interest and the developed techniques are expected to find further applications in the related nonlocal dispersal problems. We also conduct numerical simulations for a practical model to illustrate our analytical results.</div></div>","PeriodicalId":15623,"journal":{"name":"Journal of Differential Equations","volume":"462 ","pages":"Article 114144"},"PeriodicalIF":2.3,"publicationDate":"2026-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146075453","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 : 2026-01-27DOI: 10.1016/j.jde.2026.114147
Yumi Cho , Yunsoo Jang
In this research, we study a higher regularity result for elliptic problems with degenerate weights. We consider nonlinear p-Laplacian type elliptic equations related to composite materials which are composed of two or more distinct substances with different properties. Under the suitable assumptions on the nonlinearities and the geometry of composite structures, we obtain a global Calderón-Zygmund type theory.
{"title":"Global Calderón-Zygmund type theory for elliptic problems with degenerate weights from composite structures","authors":"Yumi Cho , Yunsoo Jang","doi":"10.1016/j.jde.2026.114147","DOIUrl":"10.1016/j.jde.2026.114147","url":null,"abstract":"<div><div>In this research, we study a higher regularity result for elliptic problems with degenerate weights. We consider nonlinear <em>p</em>-Laplacian type elliptic equations related to composite materials which are composed of two or more distinct substances with different properties. Under the suitable assumptions on the nonlinearities and the geometry of composite structures, we obtain a global Calderón-Zygmund type theory.</div></div>","PeriodicalId":15623,"journal":{"name":"Journal of Differential Equations","volume":"460 ","pages":"Article 114147"},"PeriodicalIF":2.3,"publicationDate":"2026-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146090700","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 : 2026-01-27DOI: 10.1016/j.jde.2026.114139
Leah Schätzler , Christoph Scheven , Jarkko Siltakoski , Calvin Stanko
We consider the Cauchy–Dirichlet problem to doubly nonlinear systems of the form with in a bounded noncylindrical domain . Further, we suppose that is integrable, that is convex, and that f satisfies a p-growth and -coercivity condition for some . Merely assuming that , we prove the existence of variational solutions . If E does not shrink too fast, we show that for the solution u constructed in the first step, admits a distributional time derivative. Moreover, under suitable conditions on E and the stricter lower bound , u is continuous with respect to time.
{"title":"Existence of variational solutions to doubly nonlinear systems in general noncylindrical domains","authors":"Leah Schätzler , Christoph Scheven , Jarkko Siltakoski , Calvin Stanko","doi":"10.1016/j.jde.2026.114139","DOIUrl":"10.1016/j.jde.2026.114139","url":null,"abstract":"<div><div>We consider the Cauchy–Dirichlet problem to doubly nonlinear systems of the form<span><span><span><math><mrow><msub><mrow><mo>∂</mo></mrow><mrow><mi>t</mi></mrow></msub><mo>(</mo><mo>|</mo><mi>u</mi><msup><mrow><mo>|</mo></mrow><mrow><mi>q</mi><mo>−</mo><mn>1</mn></mrow></msup><mi>u</mi><mo>)</mo><mo>−</mo><mi>div</mi><mo>(</mo><msub><mrow><mi>D</mi></mrow><mrow><mi>ξ</mi></mrow></msub><mi>f</mi><mo>(</mo><mi>x</mi><mo>,</mo><mi>u</mi><mo>,</mo><mi>D</mi><mi>u</mi><mo>)</mo><mo>)</mo><mo>=</mo><mo>−</mo><msub><mrow><mi>D</mi></mrow><mrow><mi>u</mi></mrow></msub><mi>f</mi><mo>(</mo><mi>x</mi><mo>,</mo><mi>u</mi><mo>,</mo><mi>D</mi><mi>u</mi><mo>)</mo></mrow></math></span></span></span> with <span><math><mi>q</mi><mo>∈</mo><mo>(</mo><mn>0</mn><mo>,</mo><mo>∞</mo><mo>)</mo></math></span> in a bounded noncylindrical domain <span><math><mi>E</mi><mo>⊂</mo><msup><mrow><mi>R</mi></mrow><mrow><mi>n</mi><mo>+</mo><mn>1</mn></mrow></msup></math></span>. Further, we suppose that <span><math><mi>x</mi><mo>↦</mo><mi>f</mi><mo>(</mo><mi>x</mi><mo>,</mo><mi>u</mi><mo>,</mo><mi>ξ</mi><mo>)</mo></math></span> is integrable, that <span><math><mo>(</mo><mi>u</mi><mo>,</mo><mi>ξ</mi><mo>)</mo><mo>↦</mo><mi>f</mi><mo>(</mo><mi>x</mi><mo>,</mo><mi>u</mi><mo>,</mo><mi>ξ</mi><mo>)</mo></math></span> is convex, and that <em>f</em> satisfies a <em>p</em>-growth and -coercivity condition for some <span><math><mi>p</mi><mo>></mo><mi>max</mi><mo></mo><mrow><mo>{</mo><mn>1</mn><mo>,</mo><mfrac><mrow><mi>n</mi><mo>(</mo><mi>q</mi><mo>+</mo><mn>1</mn><mo>)</mo></mrow><mrow><mi>n</mi><mo>+</mo><mi>q</mi><mo>+</mo><mn>1</mn></mrow></mfrac><mo>}</mo></mrow></math></span>. Merely assuming that <span><math><msup><mrow><mi>L</mi></mrow><mrow><mi>n</mi><mo>+</mo><mn>1</mn></mrow></msup><mo>(</mo><mo>∂</mo><mi>E</mi><mo>)</mo><mo>=</mo><mn>0</mn></math></span>, we prove the existence of variational solutions <span><math><mi>u</mi><mo>∈</mo><msup><mrow><mi>L</mi></mrow><mrow><mo>∞</mo></mrow></msup><mo>(</mo><mn>0</mn><mo>,</mo><mi>T</mi><mo>;</mo><msup><mrow><mi>L</mi></mrow><mrow><mi>q</mi><mo>+</mo><mn>1</mn></mrow></msup><mo>(</mo><mi>E</mi><mo>,</mo><msup><mrow><mi>R</mi></mrow><mrow><mi>N</mi></mrow></msup><mo>)</mo><mo>)</mo></math></span>. If <em>E</em> does not shrink too fast, we show that for the solution <em>u</em> constructed in the first step, <span><math><mo>|</mo><mi>u</mi><msup><mrow><mo>|</mo></mrow><mrow><mi>q</mi><mo>−</mo><mn>1</mn></mrow></msup><mi>u</mi></math></span> admits a distributional time derivative. Moreover, under suitable conditions on <em>E</em> and the stricter lower bound <span><math><mi>p</mi><mo>≥</mo><mfrac><mrow><mo>(</mo><mi>n</mi><mo>+</mo><mn>1</mn><mo>)</mo><mo>(</mo><mi>q</mi><mo>+</mo><mn>1</mn><mo>)</mo></mrow><mrow><mi>n</mi><mo>+</mo><mi>q</mi><mo>+</mo><mn>1</mn></mrow></mfrac></math></span>, <em>u</em> is continuous with respect to time.</div></div>","PeriodicalId":15623,"journal":{"name":"Journal of Differential Equations","volume":"462 ","pages":"Article 114139"},"PeriodicalIF":2.3,"publicationDate":"2026-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146075451","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 : 2026-01-26DOI: 10.1016/j.jde.2026.114143
Hai Zhou, Tao Zhou
<div><div>In this paper, we investigate the properties of the spreading speeds for the following Fisher-KPP lattice system in the almost periodic media:<span><span><span>(⁎)</span><span><math><mrow><mo>{</mo><mtable><mtr><mtd></mtd><mtd><msub><mrow><mi>u</mi></mrow><mrow><mi>t</mi></mrow></msub><mo>(</mo><mi>t</mi><mo>,</mo><mi>i</mi><mo>)</mo><mo>=</mo><msubsup><mrow><mi>d</mi></mrow><mrow><mi>i</mi></mrow><mrow><mo>′</mo></mrow></msubsup><mo>(</mo><mi>u</mi><mo>(</mo><mi>t</mi><mo>,</mo><mi>i</mi><mo>+</mo><mn>1</mn><mo>)</mo><mo>−</mo><mi>u</mi><mo>(</mo><mi>t</mi><mo>,</mo><mi>i</mi><mo>)</mo><mo>)</mo><mo>+</mo><msub><mrow><mi>d</mi></mrow><mrow><mi>i</mi></mrow></msub><mo>(</mo><mi>u</mi><mo>(</mo><mi>t</mi><mo>,</mo><mi>i</mi><mo>−</mo><mn>1</mn><mo>)</mo><mo>−</mo><mi>u</mi><mo>(</mo><mi>t</mi><mo>,</mo><mi>i</mi><mo>)</mo><mo>)</mo><mo>+</mo><mi>f</mi><mo>(</mo><mi>i</mi><mo>,</mo><mi>u</mi><mo>(</mo><mi>t</mi><mo>,</mo><mi>i</mi><mo>)</mo><mo>)</mo><mo>,</mo></mtd></mtr><mtr><mtd></mtd><mtd><mi>u</mi><mo>(</mo><mn>0</mn><mo>,</mo><mi>i</mi><mo>)</mo><mo>=</mo><msub><mrow><mi>u</mi></mrow><mrow><mn>0</mn></mrow></msub><mo>(</mo><mi>i</mi><mo>)</mo><mo>∈</mo><mo>[</mo><mn>0</mn><mo>,</mo><mn>1</mn><mo>]</mo><mspace></mspace><mtext>is nonzero with compact support</mtext><mo>.</mo></mtd></mtr></mtable></mrow></math></span></span></span> First, we prove the existence of spreading speeds <span><math><msup><mrow><mi>ω</mi></mrow><mrow><mo>+</mo></mrow></msup></math></span> and <span><math><msup><mrow><mi>ω</mi></mrow><mrow><mo>−</mo></mrow></msup></math></span> of <span><span>(⁎)</span></span> in the positive and negative directions, respectively, without the “small drift” assumption. Moreover, the difference between the speeds on both sides (i.e., which is larger) is determined by a certain average of the left and right fluxes. Specifically,<span><span><span><math><mtext>sgn</mtext><mo>(</mo><msup><mrow><mi>ω</mi></mrow><mrow><mo>+</mo></mrow></msup><mo>−</mo><msup><mrow><mi>ω</mi></mrow><mrow><mo>−</mo></mrow></msup><mo>)</mo><mo>=</mo><mtext>sgn</mtext><mo>(</mo><munder><mi>lim</mi><mrow><mi>n</mi><mo>→</mo><mo>∞</mo></mrow></munder><mo></mo><mfrac><mrow><mn>1</mn></mrow><mrow><mi>n</mi></mrow></mfrac><munderover><mo>∑</mo><mrow><mi>i</mi><mo>=</mo><mn>1</mn></mrow><mrow><mi>n</mi></mrow></munderover><mi>ln</mi><mo></mo><mfrac><mrow><msubsup><mrow><mi>d</mi></mrow><mrow><mi>i</mi></mrow><mrow><mo>′</mo></mrow></msubsup></mrow><mrow><msub><mrow><mi>d</mi></mrow><mrow><mi>i</mi></mrow></msub></mrow></mfrac><mo>)</mo><mo>.</mo></math></span></span></span> We also prove the convergence of the average in the discrete case to that in the continuous case. Additionally, we demonstrate that, in the homogeneous case, any small perturbation of the 2-periodic drift reduces the expanding spread of the level set, i.e., the value <span><math><msup><mrow><mi>ω</mi></mrow><mrow><mo>+</mo></mrow></msup><mo>+</mo><msup><mrow><mi>ω</mi></mrow><mrow><mo>−</mo
{"title":"Propagation properties of Fisher-KPP lattice equations with almost periodic coefficients","authors":"Hai Zhou, Tao Zhou","doi":"10.1016/j.jde.2026.114143","DOIUrl":"10.1016/j.jde.2026.114143","url":null,"abstract":"<div><div>In this paper, we investigate the properties of the spreading speeds for the following Fisher-KPP lattice system in the almost periodic media:<span><span><span>(⁎)</span><span><math><mrow><mo>{</mo><mtable><mtr><mtd></mtd><mtd><msub><mrow><mi>u</mi></mrow><mrow><mi>t</mi></mrow></msub><mo>(</mo><mi>t</mi><mo>,</mo><mi>i</mi><mo>)</mo><mo>=</mo><msubsup><mrow><mi>d</mi></mrow><mrow><mi>i</mi></mrow><mrow><mo>′</mo></mrow></msubsup><mo>(</mo><mi>u</mi><mo>(</mo><mi>t</mi><mo>,</mo><mi>i</mi><mo>+</mo><mn>1</mn><mo>)</mo><mo>−</mo><mi>u</mi><mo>(</mo><mi>t</mi><mo>,</mo><mi>i</mi><mo>)</mo><mo>)</mo><mo>+</mo><msub><mrow><mi>d</mi></mrow><mrow><mi>i</mi></mrow></msub><mo>(</mo><mi>u</mi><mo>(</mo><mi>t</mi><mo>,</mo><mi>i</mi><mo>−</mo><mn>1</mn><mo>)</mo><mo>−</mo><mi>u</mi><mo>(</mo><mi>t</mi><mo>,</mo><mi>i</mi><mo>)</mo><mo>)</mo><mo>+</mo><mi>f</mi><mo>(</mo><mi>i</mi><mo>,</mo><mi>u</mi><mo>(</mo><mi>t</mi><mo>,</mo><mi>i</mi><mo>)</mo><mo>)</mo><mo>,</mo></mtd></mtr><mtr><mtd></mtd><mtd><mi>u</mi><mo>(</mo><mn>0</mn><mo>,</mo><mi>i</mi><mo>)</mo><mo>=</mo><msub><mrow><mi>u</mi></mrow><mrow><mn>0</mn></mrow></msub><mo>(</mo><mi>i</mi><mo>)</mo><mo>∈</mo><mo>[</mo><mn>0</mn><mo>,</mo><mn>1</mn><mo>]</mo><mspace></mspace><mtext>is nonzero with compact support</mtext><mo>.</mo></mtd></mtr></mtable></mrow></math></span></span></span> First, we prove the existence of spreading speeds <span><math><msup><mrow><mi>ω</mi></mrow><mrow><mo>+</mo></mrow></msup></math></span> and <span><math><msup><mrow><mi>ω</mi></mrow><mrow><mo>−</mo></mrow></msup></math></span> of <span><span>(⁎)</span></span> in the positive and negative directions, respectively, without the “small drift” assumption. Moreover, the difference between the speeds on both sides (i.e., which is larger) is determined by a certain average of the left and right fluxes. Specifically,<span><span><span><math><mtext>sgn</mtext><mo>(</mo><msup><mrow><mi>ω</mi></mrow><mrow><mo>+</mo></mrow></msup><mo>−</mo><msup><mrow><mi>ω</mi></mrow><mrow><mo>−</mo></mrow></msup><mo>)</mo><mo>=</mo><mtext>sgn</mtext><mo>(</mo><munder><mi>lim</mi><mrow><mi>n</mi><mo>→</mo><mo>∞</mo></mrow></munder><mo></mo><mfrac><mrow><mn>1</mn></mrow><mrow><mi>n</mi></mrow></mfrac><munderover><mo>∑</mo><mrow><mi>i</mi><mo>=</mo><mn>1</mn></mrow><mrow><mi>n</mi></mrow></munderover><mi>ln</mi><mo></mo><mfrac><mrow><msubsup><mrow><mi>d</mi></mrow><mrow><mi>i</mi></mrow><mrow><mo>′</mo></mrow></msubsup></mrow><mrow><msub><mrow><mi>d</mi></mrow><mrow><mi>i</mi></mrow></msub></mrow></mfrac><mo>)</mo><mo>.</mo></math></span></span></span> We also prove the convergence of the average in the discrete case to that in the continuous case. Additionally, we demonstrate that, in the homogeneous case, any small perturbation of the 2-periodic drift reduces the expanding spread of the level set, i.e., the value <span><math><msup><mrow><mi>ω</mi></mrow><mrow><mo>+</mo></mrow></msup><mo>+</mo><msup><mrow><mi>ω</mi></mrow><mrow><mo>−</mo","PeriodicalId":15623,"journal":{"name":"Journal of Differential Equations","volume":"461 ","pages":"Article 114143"},"PeriodicalIF":2.3,"publicationDate":"2026-01-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146074313","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 : 2026-01-26DOI: 10.1016/j.jde.2026.114127
Alfredo J. Grados, Jeferson Cassiano, Maurício F.S. Lima, Rafael D. Vilela
On-off swimming mechanisms are common in natural and artificial microswimmers. A mathematically sound modeling of the dynamics of particles exhibiting such mechanisms should be based on discontinuous vector fields. Nevertheless, the relatively new techniques constructed to deal with discontinuous systems have not been employed for microswimmers. Here, motivated by the “run” strategy proposed in T. Mano et al. (2017) [11] for motile Janus particles, we study the dynamics of swimmers with self-propulsion when their orientation is close to a given direction. Unlike the dynamics addressed in the aforementioned reference, we consider that swimmers are immersed in a fluid flow. Their orientation, therefore, evolves according to Jeffery's equation. We use the Filippov formalism for discontinuous systems to geometrically describe the velocity field. We also derive a Poincaré map, which describes the dynamics to first order in the discontinuity parameter, and study some of its properties.
开关游泳机制在天然和人工微游泳者中很常见。表现出这种机制的粒子动力学的数学上合理的建模应该基于不连续的矢量场。然而,为处理不连续系统而构建的相对较新的技术尚未用于微游泳者。在T. Mano et al.(2017)[11]中针对运动Janus粒子提出的“奔跑”策略的激励下,我们研究了具有自我推进的游泳者在其方向接近给定方向时的动力学。与前面提到的动力学不同,我们认为游泳者沉浸在流体流动中。因此,它们的方向根据杰弗瑞的方程演变。我们用不连续系统的菲利波夫形式来几何地描述速度场。我们还得到了一个在不连续参数上描述动力学到一阶的庞卡罗映射,并研究了它的一些性质。
{"title":"Dynamics of an on-off self-propelled particle in a cellular flow","authors":"Alfredo J. Grados, Jeferson Cassiano, Maurício F.S. Lima, Rafael D. Vilela","doi":"10.1016/j.jde.2026.114127","DOIUrl":"10.1016/j.jde.2026.114127","url":null,"abstract":"<div><div>On-off swimming mechanisms are common in natural and artificial microswimmers. A mathematically sound modeling of the dynamics of particles exhibiting such mechanisms should be based on discontinuous vector fields. Nevertheless, the relatively new techniques constructed to deal with discontinuous systems have not been employed for microswimmers. Here, motivated by the “run” strategy proposed in T. Mano et al. (2017) <span><span>[11]</span></span> for motile Janus particles, we study the dynamics of swimmers with self-propulsion when their orientation is close to a given direction. Unlike the dynamics addressed in the aforementioned reference, we consider that swimmers are immersed in a fluid flow. Their orientation, therefore, evolves according to Jeffery's equation. We use the Filippov formalism for discontinuous systems to geometrically describe the velocity field. We also derive a Poincaré map, which describes the dynamics to first order in the discontinuity parameter, and study some of its properties.</div></div>","PeriodicalId":15623,"journal":{"name":"Journal of Differential Equations","volume":"462 ","pages":"Article 114127"},"PeriodicalIF":2.3,"publicationDate":"2026-01-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146075454","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 : 2026-01-26DOI: 10.1016/j.jde.2026.114155
Yingdu Dong, Xiong Li
In this paper, we focus on the existence of rotating wave solutions for a nonlinear wave equation on the sphere with , which is a kind of traveling wave solutions on non-Euclidean spaces. The case when the angular velocity is larger than 1 is of particular focus, as it leads to an elliptic-hyperbolic mixed-type equation. Generally, the spectrum of a mixed-type linearized operator could behave badly, e.g., the spectrum is unbounded from below and above, and there may exist an accumulation at zero. The aim of this paper is to address the case with accumulation points in the spectrum, which leads to the ‘small divisor problem’. Owing to the geometric structure of the sphere and the good properties of the eigenvalues of the Laplacian on it, the accumulation can occur in a controlled manner if appropriate angular velocities are selected. Then we attack this issue through the Nash-Moser type iteration theorem.
{"title":"Rotating waves for nonlinear wave equations with angular velocities on a positive-measure set","authors":"Yingdu Dong, Xiong Li","doi":"10.1016/j.jde.2026.114155","DOIUrl":"10.1016/j.jde.2026.114155","url":null,"abstract":"<div><div>In this paper, we focus on the existence of rotating wave solutions for a nonlinear wave equation on the sphere <span><math><msup><mrow><mi>S</mi></mrow><mrow><mi>d</mi><mo>−</mo><mn>1</mn></mrow></msup></math></span> with <span><math><mi>d</mi><mo>≥</mo><mn>3</mn></math></span>, which is a kind of traveling wave solutions on non-Euclidean spaces. The case when the angular velocity is larger than 1 is of particular focus, as it leads to an elliptic-hyperbolic mixed-type equation. Generally, the spectrum of a mixed-type linearized operator could behave badly, e.g., the spectrum is unbounded from below and above, and there may exist an accumulation at zero. The aim of this paper is to address the case with accumulation points in the spectrum, which leads to the ‘small divisor problem’. Owing to the geometric structure of the sphere and the good properties of the eigenvalues of the Laplacian on it, the accumulation can occur in a controlled manner if appropriate angular velocities are selected. Then we attack this issue through the Nash-Moser type iteration theorem.</div></div>","PeriodicalId":15623,"journal":{"name":"Journal of Differential Equations","volume":"462 ","pages":"Article 114155"},"PeriodicalIF":2.3,"publicationDate":"2026-01-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146075450","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 : 2026-01-23DOI: 10.1016/j.jde.2026.114133
Youjun Deng , Lingzheng Kong , Yongjian Liu , Liyan Zhu
Multi-layered structures are widely used in the construction of metamaterial devices to realize various cutting-edge waveguide applications. This paper makes several contributions to the mathematical analysis of subwavelength resonances in a structure of N-layer nested resonators. Firstly, based on the Dirichlet-to-Neumann approach, we reduce the solution of the acoustic scattering problem to an N-dimensional linear system, and derive the optimal asymptotic characterization of subwavelength resonant frequencies in terms of the eigenvalues of an tridiagonal matrix, which we refer to as the generalized capacitance matrix. Moreover, we provide a modal decomposition formula for the scattered field, as well as a monopole approximation for the far-field pattern of the acoustic wave scattered by the N-layer nested resonators. Finally, some numerical results are presented to corroborate the theoretical findings.
{"title":"Mathematical analysis of subwavelength resonant acoustic scattering in multi-layered high-contrast structures","authors":"Youjun Deng , Lingzheng Kong , Yongjian Liu , Liyan Zhu","doi":"10.1016/j.jde.2026.114133","DOIUrl":"10.1016/j.jde.2026.114133","url":null,"abstract":"<div><div>Multi-layered structures are widely used in the construction of metamaterial devices to realize various cutting-edge waveguide applications. This paper makes several contributions to the mathematical analysis of subwavelength resonances in a structure of <em>N</em>-layer nested resonators. Firstly, based on the Dirichlet-to-Neumann approach, we reduce the solution of the acoustic scattering problem to an <em>N</em>-dimensional linear system, and derive the optimal asymptotic characterization of subwavelength resonant frequencies in terms of the eigenvalues of an <span><math><mi>N</mi><mo>×</mo><mi>N</mi></math></span> tridiagonal matrix, which we refer to as the generalized capacitance matrix. Moreover, we provide a modal decomposition formula for the scattered field, as well as a monopole approximation for the far-field pattern of the acoustic wave scattered by the <em>N</em>-layer nested resonators. Finally, some numerical results are presented to corroborate the theoretical findings.</div></div>","PeriodicalId":15623,"journal":{"name":"Journal of Differential Equations","volume":"462 ","pages":"Article 114133"},"PeriodicalIF":2.3,"publicationDate":"2026-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146025657","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}