Pub Date : 2026-05-01Epub Date: 2026-01-21DOI: 10.1016/j.jfa.2026.111360
A. Defant , D. Galicer , M. Mansilla , M. Mastyło , S. Muro
We investigate projection constants for spaces of bihomogeneous harmonic and bihomogeneous polynomials on the unit sphere in finite-dimensional complex Hilbert spaces. Using averaging techniques, we demonstrate that the minimal norm projection aligns with the natural orthogonal projection. This result enables us to establish a connection between these constants and weighted -norms of specific Jacobi polynomials. Consequently, we derive explicit bounds, provide practical expressions for computation, and present asymptotically sharp estimates for these constants. Our findings extend the classical Ryll and Wojtaszczyk formula for the projection constant of homogeneous polynomials in finite-dimensional complex Hilbert spaces to the bihomogeneous setting.
{"title":"Ryll-Wojtaszczyk formulas for bihomogeneous polynomials on the sphere","authors":"A. Defant , D. Galicer , M. Mansilla , M. Mastyło , S. Muro","doi":"10.1016/j.jfa.2026.111360","DOIUrl":"10.1016/j.jfa.2026.111360","url":null,"abstract":"<div><div>We investigate projection constants for spaces of bihomogeneous harmonic and bihomogeneous polynomials on the unit sphere in finite-dimensional complex Hilbert spaces. Using averaging techniques, we demonstrate that the minimal norm projection aligns with the natural orthogonal projection. This result enables us to establish a connection between these constants and weighted <span><math><msub><mrow><mi>L</mi></mrow><mrow><mn>1</mn></mrow></msub></math></span>-norms of specific Jacobi polynomials. Consequently, we derive explicit bounds, provide practical expressions for computation, and present asymptotically sharp estimates for these constants. Our findings extend the classical Ryll and Wojtaszczyk formula for the projection constant of homogeneous polynomials in finite-dimensional complex Hilbert spaces to the bihomogeneous setting.</div></div>","PeriodicalId":15750,"journal":{"name":"Journal of Functional Analysis","volume":"290 9","pages":"Article 111360"},"PeriodicalIF":1.6,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146190811","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 : 2026-05-01Epub Date: 2026-01-22DOI: 10.1016/j.jfa.2026.111367
Ruowei Li , Florentin Münch
In this paper, we prove the convergence and uniqueness of a general discrete-time nonlinear Markov chain with specific conditions. The results have important applications in discrete differential geometry. First, we prove the discrete-time Ollivier Ricci curvature flow converges to a constant curvature metric on a finite weighted graph. As shown in [30, Theorem 5.1], a Laplacian separation principle holds on a locally finite graph with nonnegative Ollivier curvature. We further prove that the Laplacian separation flow converges to the constant Laplacian solution and generalizes the result to nonlinear p-Laplace operators. Moreover, our results can also be applied to study the long-time behavior in the nonlinear Dirichlet forms theory and nonlinear Perron-Frobenius theory. Finally, we define the Ollivier Ricci curvature of the nonlinear Markov chain which is consistent with the classical Ollivier Ricci curvature, sectional curvature [5], coarse Ricci curvature on hypergraphs [14] and the modified Ollivier Ricci curvature for p-Laplace. We also establish the convergence results for the nonlinear Markov chain with nonnegative Ollivier Ricci curvature.
{"title":"The convergence and uniqueness of a discrete-time nonlinear Markov chain","authors":"Ruowei Li , Florentin Münch","doi":"10.1016/j.jfa.2026.111367","DOIUrl":"10.1016/j.jfa.2026.111367","url":null,"abstract":"<div><div>In this paper, we prove the convergence and uniqueness of a general discrete-time nonlinear Markov chain with specific conditions. The results have important applications in discrete differential geometry. First, we prove the discrete-time Ollivier Ricci curvature flow <span><math><msub><mrow><mi>d</mi></mrow><mrow><mi>n</mi><mo>+</mo><mn>1</mn></mrow></msub><mo>≔</mo><mo>(</mo><mn>1</mn><mo>−</mo><mi>α</mi><msub><mrow><mi>κ</mi></mrow><mrow><msub><mrow><mi>d</mi></mrow><mrow><mi>n</mi></mrow></msub></mrow></msub><mo>)</mo><msub><mrow><mi>d</mi></mrow><mrow><mi>n</mi></mrow></msub></math></span> converges to a constant curvature metric on a finite weighted graph. As shown in <span><span>[30, Theorem 5.1]</span></span>, a Laplacian separation principle holds on a locally finite graph with nonnegative Ollivier curvature. We further prove that the Laplacian separation flow converges to the constant Laplacian solution and generalizes the result to nonlinear <em>p</em>-Laplace operators. Moreover, our results can also be applied to study the long-time behavior in the nonlinear Dirichlet forms theory and nonlinear Perron-Frobenius theory. Finally, we define the Ollivier Ricci curvature of the nonlinear Markov chain which is consistent with the classical Ollivier Ricci curvature, sectional curvature <span><span>[5]</span></span>, coarse Ricci curvature on hypergraphs <span><span>[14]</span></span> and the modified Ollivier Ricci curvature for <em>p</em>-Laplace. We also establish the convergence results for the nonlinear Markov chain with nonnegative Ollivier Ricci curvature.</div></div>","PeriodicalId":15750,"journal":{"name":"Journal of Functional Analysis","volume":"290 9","pages":"Article 111367"},"PeriodicalIF":1.6,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146076935","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 : 2026-05-01Epub Date: 2026-01-26DOI: 10.1016/j.jfa.2026.111380
Runmin Gong , Qiaohua Yang , Shihong Zhang
Frank et al. (2022) [38] stated that there is no relation between the reversed Hardy-Littlewood-Sobolev (HLS) inequalities and reverse Sobolev inequalities. However, we demonstrate that reverse Sobolev inequalities of order on the n-sphere can be readily derived from the reversed HLS inequalities. For the case , we present a simple proof of reverse Sobolev inequalities by using the center of mass condition introduced by Hang. In addition, applying this approach, we establish the quantitative stability of reverse Sobolev inequalities of order with explicit lower bounds. Finally, by using conformally covariant boundary operators and reverse Sobolev inequalities, we derive Sobolev trace inequalities on the unit ball.
Frank et al.(2022)[38]指出,反向Hardy-Littlewood-Sobolev (HLS)不等式与反向Sobolev不等式之间没有关系。然而,我们证明了n球上γ∈(n2,n2+1)阶的反Sobolev不等式可以很容易地由反HLS不等式导出。对于γ∈(n2+1,n2+2)的情况,利用Hang引入的质心条件,给出了逆Sobolev不等式的一个简单证明。此外,利用该方法,我们建立了γ∈(n2+1,n2+2)阶逆Sobolev不等式具有明确下界的定量稳定性。最后,利用共形协变边界算子和逆Sobolev不等式,导出了单位球上的Sobolev迹不等式。
{"title":"A simple proof of reverse Sobolev inequalities on the sphere and Sobolev trace inequalities on the unit ball","authors":"Runmin Gong , Qiaohua Yang , Shihong Zhang","doi":"10.1016/j.jfa.2026.111380","DOIUrl":"10.1016/j.jfa.2026.111380","url":null,"abstract":"<div><div>Frank et al. (2022) <span><span>[38]</span></span> stated that there is no relation between the reversed Hardy-Littlewood-Sobolev (HLS) inequalities and reverse Sobolev inequalities. However, we demonstrate that reverse Sobolev inequalities of order <span><math><mi>γ</mi><mo>∈</mo><mo>(</mo><mfrac><mrow><mi>n</mi></mrow><mrow><mn>2</mn></mrow></mfrac><mo>,</mo><mfrac><mrow><mi>n</mi></mrow><mrow><mn>2</mn></mrow></mfrac><mo>+</mo><mn>1</mn><mo>)</mo></math></span> on the <em>n</em>-sphere can be readily derived from the reversed HLS inequalities. For the case <span><math><mi>γ</mi><mo>∈</mo><mo>(</mo><mfrac><mrow><mi>n</mi></mrow><mrow><mn>2</mn></mrow></mfrac><mo>+</mo><mn>1</mn><mo>,</mo><mfrac><mrow><mi>n</mi></mrow><mrow><mn>2</mn></mrow></mfrac><mo>+</mo><mn>2</mn><mo>)</mo></math></span>, we present a simple proof of reverse Sobolev inequalities by using the center of mass condition introduced by Hang. In addition, applying this approach, we establish the quantitative stability of reverse Sobolev inequalities of order <span><math><mi>γ</mi><mo>∈</mo><mo>(</mo><mfrac><mrow><mi>n</mi></mrow><mrow><mn>2</mn></mrow></mfrac><mo>+</mo><mn>1</mn><mo>,</mo><mfrac><mrow><mi>n</mi></mrow><mrow><mn>2</mn></mrow></mfrac><mo>+</mo><mn>2</mn><mo>)</mo></math></span> with explicit lower bounds. Finally, by using conformally covariant boundary operators and reverse Sobolev inequalities, we derive Sobolev trace inequalities on the unit ball.</div></div>","PeriodicalId":15750,"journal":{"name":"Journal of Functional Analysis","volume":"290 9","pages":"Article 111380"},"PeriodicalIF":1.6,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146076937","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 : 2026-05-01Epub Date: 2026-01-23DOI: 10.1016/j.jfa.2026.111383
Xiaoxia Ren , Dongyi Wei
In this paper, we prove the stability threshold of for 2D Boussinesq equations around the Couette flow in with Richardson number and different viscosity ν and thermal diffusivity μ. More precisely, if , , , then the asymptotic stability holds. This stability threshold is consistent with the optimal stability threshold for the 2D Navier-Stokes equations in Sobolev space. And in the sense of inviscid damping effect, the regularity assumption of the initial data should be sharp.
{"title":"Transition threshold of Couette flow for 2D Boussinesq equations","authors":"Xiaoxia Ren , Dongyi Wei","doi":"10.1016/j.jfa.2026.111383","DOIUrl":"10.1016/j.jfa.2026.111383","url":null,"abstract":"<div><div>In this paper, we prove the stability threshold of <span><math><mfrac><mrow><mn>1</mn></mrow><mrow><mn>3</mn></mrow></mfrac></math></span> for 2D Boussinesq equations around the Couette flow in <span><math><mi>T</mi><mo>×</mo><mi>R</mi></math></span> with Richardson number <span><math><msup><mrow><mi>γ</mi></mrow><mrow><mn>2</mn></mrow></msup><mo>></mo><mfrac><mrow><mn>1</mn></mrow><mrow><mn>4</mn></mrow></mfrac></math></span> and different viscosity <em>ν</em> and thermal diffusivity <em>μ</em>. More precisely, if <span><math><msub><mrow><mo>‖</mo><msub><mrow><mi>v</mi></mrow><mrow><mi>i</mi><mi>n</mi></mrow></msub><mo>−</mo><mo>(</mo><mi>y</mi><mo>,</mo><mn>0</mn><mo>)</mo><mo>‖</mo></mrow><mrow><msup><mrow><mi>H</mi></mrow><mrow><mi>s</mi><mo>+</mo><mn>1</mn><mo>/</mo><mn>2</mn></mrow></msup></mrow></msub><mo>+</mo><msub><mrow><mo>‖</mo><msub><mrow><mi>ρ</mi></mrow><mrow><mi>i</mi><mi>n</mi></mrow></msub><mo>+</mo><msup><mrow><mi>γ</mi></mrow><mrow><mn>2</mn></mrow></msup><mi>y</mi><mo>−</mo><mn>1</mn><mo>‖</mo></mrow><mrow><msup><mrow><mi>H</mi></mrow><mrow><mi>s</mi><mo>+</mo><mn>1</mn><mo>/</mo><mn>2</mn></mrow></msup></mrow></msub><mo>≤</mo><mi>c</mi><msup><mrow><mo>(</mo><mi>min</mi><mo></mo><mo>{</mo><mi>ν</mi><mo>,</mo><mi>μ</mi><mo>}</mo><mo>)</mo></mrow><mrow><mn>1</mn><mo>/</mo><mn>3</mn></mrow></msup></math></span>, <span><math><mfrac><mrow><mi>ν</mi><mo>+</mo><mi>μ</mi></mrow><mrow><mn>2</mn><mi>γ</mi><msqrt><mrow><mi>ν</mi><mi>μ</mi></mrow></msqrt></mrow></mfrac><mo><</mo><mn>2</mn><mo>−</mo><mi>ε</mi></math></span>, <span><math><mi>s</mi><mo>></mo><mfrac><mrow><mn>3</mn></mrow><mrow><mn>2</mn></mrow></mfrac></math></span>, then the asymptotic stability holds. This stability threshold is consistent with the optimal stability threshold for the 2D Navier-Stokes equations in Sobolev space. And in the sense of inviscid damping effect, the regularity assumption of the initial data should be sharp.</div></div>","PeriodicalId":15750,"journal":{"name":"Journal of Functional Analysis","volume":"290 9","pages":"Article 111383"},"PeriodicalIF":1.6,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146190808","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 : 2026-05-01Epub Date: 2026-01-23DOI: 10.1016/j.jfa.2026.111376
Josephine Evans , Daniel Morris , Havva Yoldaş
We consider a class of nonlinear, spatially inhomogeneous kinetic equations of BGK-type with density dependent collision rates. These equations share the same superlinearity as the Boltzmann equation, and fall into the class of run and tumble equations appearing in mathematical biology. We prove that the Cauchy problem is well-posed, and the solutions propagate Maxwellian bounds over time. Moreover, we show that the solutions approach to equilibrium with an exponential rate, known as a hypocoercivity result. Lastly, we derive a class of nonlinear diffusion equations as the hydrodynamic limit of the kinetic equations in the diffusive scaling, employing both hypocoercivity and relative entropy methods. The limit equations cover a wide range of nonlinear diffusion equations including both the porous medium and the fast diffusion equations.
{"title":"On a class of nonlinear BGK-type kinetic equations with density dependent collision rates","authors":"Josephine Evans , Daniel Morris , Havva Yoldaş","doi":"10.1016/j.jfa.2026.111376","DOIUrl":"10.1016/j.jfa.2026.111376","url":null,"abstract":"<div><div>We consider a class of nonlinear, spatially inhomogeneous kinetic equations of BGK-type with density dependent collision rates. These equations share the same superlinearity as the Boltzmann equation, and fall into the class of run and tumble equations appearing in mathematical biology. We prove that the Cauchy problem is well-posed, and the solutions propagate Maxwellian bounds over time. Moreover, we show that the solutions approach to equilibrium with an exponential rate, known as a hypocoercivity result. Lastly, we derive a class of nonlinear diffusion equations as the hydrodynamic limit of the kinetic equations in the diffusive scaling, employing both hypocoercivity and relative entropy methods. The limit equations cover a wide range of nonlinear diffusion equations including both the porous medium and the fast diffusion equations.</div></div>","PeriodicalId":15750,"journal":{"name":"Journal of Functional Analysis","volume":"290 9","pages":"Article 111376"},"PeriodicalIF":1.6,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146057597","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 : 2026-05-01Epub Date: 2026-01-22DOI: 10.1016/j.jfa.2026.111359
Rodrigo Bañuelos , Daesung Kim , Mateusz Kwaśnicki
This paper investigates higher dimensional versions of the longstanding conjecture verified in [11] that the -norm of the discrete Hilbert transform on the integers is the same as the -norm of the Hilbert transform on the real line. It computes the -norms of a family of discrete operators on the lattice , . They are discretizations of a new class of singular integrals on that have the same kernels as the classical Riesz transforms near zero and similar behavior at infinity. The discrete operators have the same p-norms as the classical Riesz transforms on . They are constructed as conditional expectations of martingale transforms of Doob h-processes conditioned to exit the upper-half space only on the lattice . The paper also presents a discrete analogue of the classical method of rotations which gives the norm of a different variant of discrete Riesz transforms on . Along the way a new proof is given based on Fourier transform techniques of the key identity used to identify the norm of the discrete Hilbert transform in [11]. Open problems are stated.
{"title":"Sharp ℓp inequalities for discrete singular integrals on the lattice Zd","authors":"Rodrigo Bañuelos , Daesung Kim , Mateusz Kwaśnicki","doi":"10.1016/j.jfa.2026.111359","DOIUrl":"10.1016/j.jfa.2026.111359","url":null,"abstract":"<div><div>This paper investigates higher dimensional versions of the longstanding conjecture verified in <span><span>[11]</span></span> that the <span><math><msup><mrow><mi>ℓ</mi></mrow><mrow><mi>p</mi></mrow></msup></math></span>-norm of the discrete Hilbert transform on the integers is the same as the <span><math><msup><mrow><mi>L</mi></mrow><mrow><mi>p</mi></mrow></msup></math></span>-norm of the Hilbert transform on the real line. It computes the <span><math><msup><mrow><mi>ℓ</mi></mrow><mrow><mi>p</mi></mrow></msup></math></span>-norms of a family of discrete operators on the lattice <span><math><msup><mrow><mi>Z</mi></mrow><mrow><mi>d</mi></mrow></msup></math></span>, <span><math><mi>d</mi><mo>≥</mo><mn>1</mn></math></span>. They are discretizations of a new class of singular integrals on <span><math><msup><mrow><mi>R</mi></mrow><mrow><mi>d</mi></mrow></msup></math></span> that have the same kernels as the classical Riesz transforms near zero and similar behavior at infinity. The discrete operators have the same <em>p</em>-norms as the classical Riesz transforms on <span><math><msup><mrow><mi>R</mi></mrow><mrow><mi>d</mi></mrow></msup></math></span>. They are constructed as conditional expectations of martingale transforms of Doob h-processes conditioned to exit the upper-half space <span><math><msup><mrow><mi>R</mi></mrow><mrow><mi>d</mi></mrow></msup><mo>×</mo><msub><mrow><mi>R</mi></mrow><mrow><mo>+</mo></mrow></msub></math></span> only on the lattice <span><math><msup><mrow><mi>Z</mi></mrow><mrow><mi>d</mi></mrow></msup></math></span>. The paper also presents a discrete analogue of the classical method of rotations which gives the norm of a different variant of discrete Riesz transforms on <span><math><msup><mrow><mi>Z</mi></mrow><mrow><mi>d</mi></mrow></msup></math></span>. Along the way a new proof is given based on Fourier transform techniques of the key identity used to identify the norm of the discrete Hilbert transform in <span><span>[11]</span></span>. Open problems are stated.</div></div>","PeriodicalId":15750,"journal":{"name":"Journal of Functional Analysis","volume":"290 9","pages":"Article 111359"},"PeriodicalIF":1.6,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146057598","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 : 2026-05-01Epub Date: 2026-01-22DOI: 10.1016/j.jfa.2026.111375
Luca Seemungal, Ben Sharp
We prove a linear upper bound on the Morse index of closed constant mean curvature (CMC) surfaces in orientable three-manifolds in terms of genus, number of branch points and a Willmore-type energy.
{"title":"Index estimates for constant mean curvature surfaces in three-manifolds by energy comparison","authors":"Luca Seemungal, Ben Sharp","doi":"10.1016/j.jfa.2026.111375","DOIUrl":"10.1016/j.jfa.2026.111375","url":null,"abstract":"<div><div>We prove a linear upper bound on the Morse index of closed constant mean curvature (CMC) surfaces in orientable three-manifolds in terms of genus, number of branch points and a Willmore-type energy.</div></div>","PeriodicalId":15750,"journal":{"name":"Journal of Functional Analysis","volume":"290 9","pages":"Article 111375"},"PeriodicalIF":1.6,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146057599","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 : 2026-05-01Epub Date: 2026-02-05DOI: 10.1016/j.jfa.2026.111385
Jake Fillman , Michala N. Gradner , Hannah J. Hendricks
We establish a new and simple criterion that suffices to generate many spectral gaps for periodic word models. This leads to new examples of ergodic Schrödinger operators with Cantor spectra having zero Hausdorff dimension that simultaneously may have arbitrarily small supremum norm together with arbitrarily long runs on which the potential vanishes.
{"title":"Thin spectra for periodic and ergodic word models","authors":"Jake Fillman , Michala N. Gradner , Hannah J. Hendricks","doi":"10.1016/j.jfa.2026.111385","DOIUrl":"10.1016/j.jfa.2026.111385","url":null,"abstract":"<div><div>We establish a new and simple criterion that suffices to generate many spectral gaps for periodic word models. This leads to new examples of ergodic Schrödinger operators with Cantor spectra having zero Hausdorff dimension that simultaneously may have arbitrarily small supremum norm together with arbitrarily long runs on which the potential vanishes.</div></div>","PeriodicalId":15750,"journal":{"name":"Journal of Functional Analysis","volume":"290 9","pages":"Article 111385"},"PeriodicalIF":1.6,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146190809","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 : 2026-05-01Epub Date: 2026-01-23DOI: 10.1016/j.jfa.2026.111377
Jiahui Zhu , Wei Liu , Jianliang Zhai
In this work we establish a Freidlin-Wentzell type large deviation principle for stochastic nonlinear Schrödinger equation, with either focusing or defocusing nonlinearity, driven by nonlinear multiplicative Lévy noise in the Marcus canonical form. This task is challenging in the current setting due to the presence of the power-type nonlinear term, the lack of regularization effect of the Schrödinger operator and the absence of compactness of embeddings. To overcome these difficulties, we employ a regularization procedure based on Yosida approximations and implement techniques such as time discretization, cut-off arguments, and relative entropy estimates of sequences of probability measures. Our innovative approach circumvents the need for compactness conditions, distinguishing our work from previous studies.
{"title":"Large deviation principles for stochastic nonlinear Schrödinger equations driven by Lévy noise","authors":"Jiahui Zhu , Wei Liu , Jianliang Zhai","doi":"10.1016/j.jfa.2026.111377","DOIUrl":"10.1016/j.jfa.2026.111377","url":null,"abstract":"<div><div>In this work we establish a Freidlin-Wentzell type large deviation principle for stochastic nonlinear Schrödinger equation, with either focusing or defocusing nonlinearity, driven by nonlinear multiplicative Lévy noise in the Marcus canonical form. This task is challenging in the current setting due to the presence of the power-type nonlinear term, the lack of regularization effect of the Schrödinger operator and the absence of compactness of embeddings. To overcome these difficulties, we employ a regularization procedure based on Yosida approximations and implement techniques such as time discretization, cut-off arguments, and relative entropy estimates of sequences of probability measures. Our innovative approach circumvents the need for compactness conditions, distinguishing our work from previous studies.</div></div>","PeriodicalId":15750,"journal":{"name":"Journal of Functional Analysis","volume":"290 9","pages":"Article 111377"},"PeriodicalIF":1.6,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146076936","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 : 2026-05-01Epub Date: 2026-01-23DOI: 10.1016/j.jfa.2026.111378
Wencai Liu , Matthew Powell , Xueyin Wang
We employ Weyl's method and Vinogradov's method to analyze skew-shift dynamics on semi-algebraic sets. Consequently, we improve the quantum dynamical upper bounds of Jitomirskaya-Powell, Liu, and Shamis-Sodin for long-range operators with skew-shift potentials.
{"title":"Quantum dynamical bounds for long-range operators with skew-shift potentials","authors":"Wencai Liu , Matthew Powell , Xueyin Wang","doi":"10.1016/j.jfa.2026.111378","DOIUrl":"10.1016/j.jfa.2026.111378","url":null,"abstract":"<div><div>We employ Weyl's method and Vinogradov's method to analyze skew-shift dynamics on semi-algebraic sets. Consequently, we improve the quantum dynamical upper bounds of Jitomirskaya-Powell, Liu, and Shamis-Sodin for long-range operators with skew-shift potentials.</div></div>","PeriodicalId":15750,"journal":{"name":"Journal of Functional Analysis","volume":"290 9","pages":"Article 111378"},"PeriodicalIF":1.6,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146190812","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}