Pub Date : 2025-12-08DOI: 10.1016/j.jfa.2025.111306
Jonah A.J. Duncan , Luc Nguyen
<div><div>Let <span><math><mo>(</mo><msup><mrow><mi>M</mi></mrow><mrow><mi>n</mi></mrow></msup><mo>,</mo><msub><mrow><mi>g</mi></mrow><mrow><mn>0</mn></mrow></msub><mo>)</mo></math></span> be a smooth compact Riemannian manifold of dimension <span><math><mi>n</mi><mo>≥</mo><mn>3</mn></math></span> with smooth non-empty boundary ∂<em>M</em>. Let <span><math><mi>Γ</mi><mo>⊂</mo><msup><mrow><mi>R</mi></mrow><mrow><mi>n</mi></mrow></msup></math></span> be a symmetric convex cone and <em>f</em> a symmetric defining function for Γ satisfying standard assumptions. Denoting by <span><math><msub><mrow><mi>A</mi></mrow><mrow><msub><mrow><mi>g</mi></mrow><mrow><mi>u</mi></mrow></msub></mrow></msub></math></span> the Schouten tensor of a conformal metric <span><math><msub><mrow><mi>g</mi></mrow><mrow><mi>u</mi></mrow></msub><mo>=</mo><msup><mrow><mi>u</mi></mrow><mrow><mo>−</mo><mn>2</mn></mrow></msup><msub><mrow><mi>g</mi></mrow><mrow><mn>0</mn></mrow></msub></math></span>, we show that the associated fully nonlinear Loewner-Nirenberg problem<span><span><span><math><mrow><mrow><mo>{</mo><mtable><mtr><mtd><mi>f</mi><mo>(</mo><mi>λ</mi><mo>(</mo><mo>−</mo><msubsup><mrow><mi>g</mi></mrow><mrow><mi>u</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msubsup><msub><mrow><mi>A</mi></mrow><mrow><msub><mrow><mi>g</mi></mrow><mrow><mi>u</mi></mrow></msub></mrow></msub><mo>)</mo><mo>)</mo><mo>=</mo><mfrac><mrow><mn>1</mn></mrow><mrow><mn>2</mn></mrow></mfrac><mo>,</mo><mspace></mspace><mi>λ</mi><mo>(</mo><mo>−</mo><msubsup><mrow><mi>g</mi></mrow><mrow><mi>u</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msubsup><msub><mrow><mi>A</mi></mrow><mrow><msub><mrow><mi>g</mi></mrow><mrow><mi>u</mi></mrow></msub></mrow></msub><mo>)</mo><mo>∈</mo><mi>Γ</mi></mtd><mtd><mtext>on </mtext><mi>M</mi><mo>﹨</mo><mo>∂</mo><mi>M</mi></mtd></mtr><mtr><mtd><mi>u</mi><mo>=</mo><mn>0</mn></mtd><mtd><mtext>on </mtext><mo>∂</mo><mi>M</mi></mtd></mtr></mtable></mrow></mrow></math></span></span></span> admits a solution if <span><math><msubsup><mrow><mi>μ</mi></mrow><mrow><mi>Γ</mi></mrow><mrow><mo>+</mo></mrow></msubsup><mo>></mo><mn>1</mn><mo>−</mo><mi>δ</mi></math></span>, where <span><math><msubsup><mrow><mi>μ</mi></mrow><mrow><mi>Γ</mi></mrow><mrow><mo>+</mo></mrow></msubsup></math></span> is defined by <span><math><mo>(</mo><mo>−</mo><msubsup><mrow><mi>μ</mi></mrow><mrow><mi>Γ</mi></mrow><mrow><mo>+</mo></mrow></msubsup><mo>,</mo><mn>1</mn><mo>,</mo><mo>…</mo><mo>,</mo><mn>1</mn><mo>)</mo><mo>∈</mo><mo>∂</mo><mi>Γ</mi></math></span> and <span><math><mi>δ</mi><mo>></mo><mn>0</mn></math></span> is a constant depending on certain geometric data. In particular, we solve the <span><math><msub><mrow><mi>σ</mi></mrow><mrow><mi>k</mi></mrow></msub></math></span>-Loewner-Nirenberg problem for all <span><math><mi>k</mi><mo>≤</mo><mfrac><mrow><mi>n</mi></mrow><mrow><mn>2</mn></mrow></mfrac></math></span>, which extends recent work of the authors to include the important threshold case <span><math>
{"title":"The σk-Loewner-Nirenberg problem on Riemannian manifolds for k=n2 and beyond","authors":"Jonah A.J. Duncan , Luc Nguyen","doi":"10.1016/j.jfa.2025.111306","DOIUrl":"10.1016/j.jfa.2025.111306","url":null,"abstract":"<div><div>Let <span><math><mo>(</mo><msup><mrow><mi>M</mi></mrow><mrow><mi>n</mi></mrow></msup><mo>,</mo><msub><mrow><mi>g</mi></mrow><mrow><mn>0</mn></mrow></msub><mo>)</mo></math></span> be a smooth compact Riemannian manifold of dimension <span><math><mi>n</mi><mo>≥</mo><mn>3</mn></math></span> with smooth non-empty boundary ∂<em>M</em>. Let <span><math><mi>Γ</mi><mo>⊂</mo><msup><mrow><mi>R</mi></mrow><mrow><mi>n</mi></mrow></msup></math></span> be a symmetric convex cone and <em>f</em> a symmetric defining function for Γ satisfying standard assumptions. Denoting by <span><math><msub><mrow><mi>A</mi></mrow><mrow><msub><mrow><mi>g</mi></mrow><mrow><mi>u</mi></mrow></msub></mrow></msub></math></span> the Schouten tensor of a conformal metric <span><math><msub><mrow><mi>g</mi></mrow><mrow><mi>u</mi></mrow></msub><mo>=</mo><msup><mrow><mi>u</mi></mrow><mrow><mo>−</mo><mn>2</mn></mrow></msup><msub><mrow><mi>g</mi></mrow><mrow><mn>0</mn></mrow></msub></math></span>, we show that the associated fully nonlinear Loewner-Nirenberg problem<span><span><span><math><mrow><mrow><mo>{</mo><mtable><mtr><mtd><mi>f</mi><mo>(</mo><mi>λ</mi><mo>(</mo><mo>−</mo><msubsup><mrow><mi>g</mi></mrow><mrow><mi>u</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msubsup><msub><mrow><mi>A</mi></mrow><mrow><msub><mrow><mi>g</mi></mrow><mrow><mi>u</mi></mrow></msub></mrow></msub><mo>)</mo><mo>)</mo><mo>=</mo><mfrac><mrow><mn>1</mn></mrow><mrow><mn>2</mn></mrow></mfrac><mo>,</mo><mspace></mspace><mi>λ</mi><mo>(</mo><mo>−</mo><msubsup><mrow><mi>g</mi></mrow><mrow><mi>u</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msubsup><msub><mrow><mi>A</mi></mrow><mrow><msub><mrow><mi>g</mi></mrow><mrow><mi>u</mi></mrow></msub></mrow></msub><mo>)</mo><mo>∈</mo><mi>Γ</mi></mtd><mtd><mtext>on </mtext><mi>M</mi><mo>﹨</mo><mo>∂</mo><mi>M</mi></mtd></mtr><mtr><mtd><mi>u</mi><mo>=</mo><mn>0</mn></mtd><mtd><mtext>on </mtext><mo>∂</mo><mi>M</mi></mtd></mtr></mtable></mrow></mrow></math></span></span></span> admits a solution if <span><math><msubsup><mrow><mi>μ</mi></mrow><mrow><mi>Γ</mi></mrow><mrow><mo>+</mo></mrow></msubsup><mo>></mo><mn>1</mn><mo>−</mo><mi>δ</mi></math></span>, where <span><math><msubsup><mrow><mi>μ</mi></mrow><mrow><mi>Γ</mi></mrow><mrow><mo>+</mo></mrow></msubsup></math></span> is defined by <span><math><mo>(</mo><mo>−</mo><msubsup><mrow><mi>μ</mi></mrow><mrow><mi>Γ</mi></mrow><mrow><mo>+</mo></mrow></msubsup><mo>,</mo><mn>1</mn><mo>,</mo><mo>…</mo><mo>,</mo><mn>1</mn><mo>)</mo><mo>∈</mo><mo>∂</mo><mi>Γ</mi></math></span> and <span><math><mi>δ</mi><mo>></mo><mn>0</mn></math></span> is a constant depending on certain geometric data. In particular, we solve the <span><math><msub><mrow><mi>σ</mi></mrow><mrow><mi>k</mi></mrow></msub></math></span>-Loewner-Nirenberg problem for all <span><math><mi>k</mi><mo>≤</mo><mfrac><mrow><mi>n</mi></mrow><mrow><mn>2</mn></mrow></mfrac></math></span>, which extends recent work of the authors to include the important threshold case <span><math>","PeriodicalId":15750,"journal":{"name":"Journal of Functional Analysis","volume":"290 6","pages":"Article 111306"},"PeriodicalIF":1.6,"publicationDate":"2025-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145734862","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 : 2025-12-08DOI: 10.1016/j.jfa.2025.111309
Xuehan Hu , Grigoris Paouris
We study the small ball probability of an order-ℓ simple random tensor where are independent random vectors in that are log-concave or have independent coordinates with bounded densities. We show that the probability that the projection of X onto an m-dimensional subspace F falls within a Euclidean ball of length ε is upper bounded by and also this upper bound is sharp when m is small. We also established that a much better estimate holds true for a random subspace.
{"title":"Small ball probabilities for simple random tensors","authors":"Xuehan Hu , Grigoris Paouris","doi":"10.1016/j.jfa.2025.111309","DOIUrl":"10.1016/j.jfa.2025.111309","url":null,"abstract":"<div><div>We study the small ball probability of an order-<em>ℓ</em> simple random tensor <span><math><mi>X</mi><mo>=</mo><msup><mrow><mi>X</mi></mrow><mrow><mo>(</mo><mn>1</mn><mo>)</mo></mrow></msup><mo>⊗</mo><mo>⋯</mo><mo>⊗</mo><msup><mrow><mi>X</mi></mrow><mrow><mo>(</mo><mi>ℓ</mi><mo>)</mo></mrow></msup></math></span> where <span><math><msup><mrow><mi>X</mi></mrow><mrow><mo>(</mo><mi>i</mi><mo>)</mo></mrow></msup><mo>,</mo><mn>1</mn><mo>≤</mo><mi>i</mi><mo>≤</mo><mi>ℓ</mi></math></span> are independent random vectors in <span><math><msup><mrow><mi>R</mi></mrow><mrow><mi>n</mi></mrow></msup></math></span> that are log-concave or have independent coordinates with bounded densities. We show that the probability that the projection of <em>X</em> onto an <em>m</em>-dimensional subspace <em>F</em> falls within a Euclidean ball of length <em>ε</em> is upper bounded by <span><math><mfrac><mrow><mi>ε</mi></mrow><mrow><mo>(</mo><mi>ℓ</mi><mo>−</mo><mn>1</mn><mo>)</mo><mo>!</mo></mrow></mfrac><msup><mrow><mo>(</mo><mi>C</mi><mi>log</mi><mo></mo><mrow><mo>(</mo><mfrac><mrow><mn>1</mn></mrow><mrow><mi>ε</mi></mrow></mfrac><mo>)</mo></mrow><mo>)</mo></mrow><mrow><mi>ℓ</mi></mrow></msup></math></span> and also this upper bound is sharp when <em>m</em> is small. We also established that a much better estimate holds true for a random subspace.</div></div>","PeriodicalId":15750,"journal":{"name":"Journal of Functional Analysis","volume":"290 6","pages":"Article 111309"},"PeriodicalIF":1.6,"publicationDate":"2025-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145734876","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 : 2025-12-08DOI: 10.1016/j.jfa.2025.111308
Chu-hee Cho , Sanghyuk Lee , Wenjuan Li
We consider the – maximal estimates associated to the wave operator Rogers–Villarroya proved – estimates for the maximal operator f↦ up to the critical Sobolev exponents . However, the endpoint case estimates for the critical exponent have remained open so far. We obtain the endpoint – bounds on the maximal operator . We also prove that several different forms of the maximal estimates considered by Rogers–Villarroya are basically equivalent to each other.
{"title":"Endpoint estimates for maximal operators associated to the wave equation","authors":"Chu-hee Cho , Sanghyuk Lee , Wenjuan Li","doi":"10.1016/j.jfa.2025.111308","DOIUrl":"10.1016/j.jfa.2025.111308","url":null,"abstract":"<div><div>We consider the <span><math><msup><mrow><mi>H</mi></mrow><mrow><mi>s</mi></mrow></msup></math></span>–<span><math><msup><mrow><mi>L</mi></mrow><mrow><mi>q</mi></mrow></msup></math></span> maximal estimates associated to the wave operator<span><span><span><math><msup><mrow><mi>e</mi></mrow><mrow><mi>i</mi><mi>t</mi><msqrt><mrow><mo>−</mo><mi>Δ</mi></mrow></msqrt></mrow></msup><mi>f</mi><mo>(</mo><mi>x</mi><mo>)</mo><mo>=</mo><mfrac><mrow><mn>1</mn></mrow><mrow><msup><mrow><mo>(</mo><mn>2</mn><mi>π</mi><mo>)</mo></mrow><mrow><mi>d</mi></mrow></msup></mrow></mfrac><munder><mo>∫</mo><mrow><msup><mrow><mi>R</mi></mrow><mrow><mi>d</mi></mrow></msup></mrow></munder><msup><mrow><mi>e</mi></mrow><mrow><mi>i</mi><mo>(</mo><mi>x</mi><mo>⋅</mo><mi>ξ</mi><mspace></mspace><mo>+</mo><mi>t</mi><mo>|</mo><mi>ξ</mi><mo>|</mo><mo>)</mo></mrow></msup><mover><mrow><mi>f</mi></mrow><mrow><mo>ˆ</mo></mrow></mover><mo>(</mo><mi>ξ</mi><mspace></mspace><mo>)</mo><mi>d</mi><mi>ξ</mi><mo>.</mo></math></span></span></span> Rogers–Villarroya proved <span><math><msup><mrow><mi>H</mi></mrow><mrow><mi>s</mi></mrow></msup></math></span>–<span><math><msup><mrow><mi>L</mi></mrow><mrow><mi>q</mi></mrow></msup></math></span> estimates for the maximal operator <em>f</em>↦ <span><math><msub><mrow><mi>sup</mi></mrow><mrow><mi>t</mi></mrow></msub><mo></mo><mo>|</mo><msup><mrow><mi>e</mi></mrow><mrow><mi>i</mi><mi>t</mi><msqrt><mrow><mo>−</mo><mi>Δ</mi></mrow></msqrt></mrow></msup><mi>f</mi><mo>|</mo></math></span> up to the critical Sobolev exponents <span><math><msub><mrow><mi>s</mi></mrow><mrow><mi>c</mi></mrow></msub><mo>(</mo><mi>q</mi><mo>,</mo><mi>d</mi><mo>)</mo></math></span>. However, the endpoint case estimates for the critical exponent <span><math><mi>s</mi><mo>=</mo><msub><mrow><mi>s</mi></mrow><mrow><mi>c</mi></mrow></msub><mo>(</mo><mi>q</mi><mo>,</mo><mi>d</mi><mo>)</mo></math></span> have remained open so far. We obtain the endpoint <span><math><msup><mrow><mi>H</mi></mrow><mrow><msub><mrow><mi>s</mi></mrow><mrow><mi>c</mi></mrow></msub><mo>(</mo><mi>q</mi><mo>,</mo><mi>d</mi><mo>)</mo></mrow></msup></math></span>–<span><math><msup><mrow><mi>L</mi></mrow><mrow><mi>q</mi></mrow></msup></math></span> bounds on the maximal operator <span><math><mi>f</mi><mo>↦</mo><msub><mrow><mi>sup</mi></mrow><mrow><mi>t</mi></mrow></msub><mo></mo><mo>|</mo><msup><mrow><mi>e</mi></mrow><mrow><mi>i</mi><mi>t</mi><msqrt><mrow><mo>−</mo><mi>Δ</mi></mrow></msqrt></mrow></msup><mi>f</mi><mo>|</mo></math></span>. We also prove that several different forms of the maximal estimates considered by Rogers–Villarroya are basically equivalent to each other.</div></div>","PeriodicalId":15750,"journal":{"name":"Journal of Functional Analysis","volume":"290 6","pages":"Article 111308"},"PeriodicalIF":1.6,"publicationDate":"2025-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145734863","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 : 2025-12-08DOI: 10.1016/j.jfa.2025.111303
Miki Hirano , Taku Ishii , Tadashi Miyazaki
We give explicit formulas of Whittaker functions on for all irreducible generic representations.
给出了GL(4,R)上所有不可约泛型表示的惠特克函数的显式公式。
{"title":"Whittaker functions on GL(4,R)","authors":"Miki Hirano , Taku Ishii , Tadashi Miyazaki","doi":"10.1016/j.jfa.2025.111303","DOIUrl":"10.1016/j.jfa.2025.111303","url":null,"abstract":"<div><div>We give explicit formulas of Whittaker functions on <span><math><mrow><mi>GL</mi></mrow><mo>(</mo><mn>4</mn><mo>,</mo><mi>R</mi><mo>)</mo></math></span> for all irreducible generic representations.</div></div>","PeriodicalId":15750,"journal":{"name":"Journal of Functional Analysis","volume":"290 6","pages":"Article 111303"},"PeriodicalIF":1.6,"publicationDate":"2025-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145787932","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 : 2025-12-08DOI: 10.1016/j.jfa.2025.111310
Jingbo Xia
We settle the issue of Berger-Coburn phenomenon on the Fock space completely for general symmetrically normed ideals , where Φ is not equivalent to . We show that if the Boyd indices of satisfy the condition , then for , we have if and only if . We further show that if either or , then there is an such that while .
{"title":"Boyd indices and the Berger-Coburn phenomenon","authors":"Jingbo Xia","doi":"10.1016/j.jfa.2025.111310","DOIUrl":"10.1016/j.jfa.2025.111310","url":null,"abstract":"<div><div>We settle the issue of Berger-Coburn phenomenon on the Fock space completely for general symmetrically normed ideals <span><math><msub><mrow><mi>C</mi></mrow><mrow><mi>Φ</mi></mrow></msub></math></span>, where Φ is not equivalent to <span><math><msub><mrow><mi>Φ</mi></mrow><mrow><mo>∞</mo></mrow></msub></math></span>. We show that if the Boyd indices of <span><math><msub><mrow><mi>C</mi></mrow><mrow><mi>Φ</mi></mrow></msub></math></span> satisfy the condition <span><math><mn>1</mn><mo><</mo><msub><mrow><mi>p</mi></mrow><mrow><mi>Φ</mi></mrow></msub><mo>≤</mo><msub><mrow><mi>q</mi></mrow><mrow><mi>Φ</mi></mrow></msub><mo><</mo><mo>∞</mo></math></span>, then for <span><math><mi>f</mi><mo>∈</mo><msup><mrow><mi>L</mi></mrow><mrow><mo>∞</mo></mrow></msup><mo>(</mo><msup><mrow><mi>C</mi></mrow><mrow><mi>n</mi></mrow></msup><mo>)</mo></math></span>, we have <span><math><msub><mrow><mi>H</mi></mrow><mrow><mi>f</mi></mrow></msub><mo>∈</mo><msub><mrow><mi>C</mi></mrow><mrow><mi>Φ</mi></mrow></msub></math></span> if and only if <span><math><msub><mrow><mi>H</mi></mrow><mrow><mover><mrow><mi>f</mi></mrow><mrow><mo>¯</mo></mrow></mover></mrow></msub><mo>∈</mo><msub><mrow><mi>C</mi></mrow><mrow><mi>Φ</mi></mrow></msub></math></span>. We further show that if either <span><math><msub><mrow><mi>p</mi></mrow><mrow><mi>Φ</mi></mrow></msub><mo>=</mo><mn>1</mn></math></span> or <span><math><msub><mrow><mi>q</mi></mrow><mrow><mi>Φ</mi></mrow></msub><mo>=</mo><mo>∞</mo></math></span>, then there is an <span><math><mi>f</mi><mo>∈</mo><msup><mrow><mi>L</mi></mrow><mrow><mo>∞</mo></mrow></msup><mo>(</mo><msup><mrow><mi>C</mi></mrow><mrow><mi>n</mi></mrow></msup><mo>)</mo></math></span> such that <span><math><msub><mrow><mi>H</mi></mrow><mrow><mi>f</mi></mrow></msub><mo>∈</mo><msub><mrow><mi>C</mi></mrow><mrow><mi>Φ</mi></mrow></msub></math></span> while <span><math><msub><mrow><mi>H</mi></mrow><mrow><mover><mrow><mi>f</mi></mrow><mrow><mo>¯</mo></mrow></mover></mrow></msub><mo>∉</mo><msub><mrow><mi>C</mi></mrow><mrow><mi>Φ</mi></mrow></msub></math></span>.</div></div>","PeriodicalId":15750,"journal":{"name":"Journal of Functional Analysis","volume":"290 6","pages":"Article 111310"},"PeriodicalIF":1.6,"publicationDate":"2025-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145734877","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 : 2025-12-08DOI: 10.1016/j.jfa.2025.111300
Fernando de Ávila Silva , Marco Cappiello , Alexandre Kirilov
We investigate the global hypoellipticity of a class of overdetermined systems with coefficients depending both on time and space variables in the setting of time-periodic Gelfand-Shilov spaces. Our main result provides necessary and sufficient conditions for the global hypoellipticity of this class of systems, stated in terms of Diophantine-type estimates and sign-changing behavior of the imaginary parts of the coefficients. Through a reduction to a normal form and detailed construction of singular solutions, we fully characterize when the system fails to be globally hypoelliptic.
{"title":"Global hypoellipticity for systems in time-periodic Gelfand-Shilov spaces","authors":"Fernando de Ávila Silva , Marco Cappiello , Alexandre Kirilov","doi":"10.1016/j.jfa.2025.111300","DOIUrl":"10.1016/j.jfa.2025.111300","url":null,"abstract":"<div><div>We investigate the global hypoellipticity of a class of overdetermined systems with coefficients depending both on time and space variables in the setting of time-periodic Gelfand-Shilov spaces. Our main result provides necessary and sufficient conditions for the global hypoellipticity of this class of systems, stated in terms of Diophantine-type estimates and sign-changing behavior of the imaginary parts of the coefficients. Through a reduction to a normal form and detailed construction of singular solutions, we fully characterize when the system fails to be globally hypoelliptic.</div></div>","PeriodicalId":15750,"journal":{"name":"Journal of Functional Analysis","volume":"290 6","pages":"Article 111300"},"PeriodicalIF":1.6,"publicationDate":"2025-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145734878","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 : 2025-12-08DOI: 10.1016/j.jfa.2025.111302
Jerry R. Muir Jr.
We provide an assortment of integral representations of continuous linear functionals on complex and real subspaces of the space of holomorphic mappings from the open Euclidean unit ball of into . For complex or real linear functionals ℓ, our main results give representations of the form respectively, where μ is a complex Borel measure in the complex case or a finite signed or positive Borel measure in the real case, is a sphere centered at the origin, and the Hermitian inner product in is denoted in the integrands. The complex representation broadly applies to closed complex subspaces of , while the real versions assume various restrictions on real subspaces of whose necessity is explored. Several other representations stem from the main results.
{"title":"Integral representations of linear functionals on spaces of holomorphic mappings in the unit ball of Cn","authors":"Jerry R. Muir Jr.","doi":"10.1016/j.jfa.2025.111302","DOIUrl":"10.1016/j.jfa.2025.111302","url":null,"abstract":"<div><div>We provide an assortment of integral representations of continuous linear functionals on complex and real subspaces of the space <span><math><mi>H</mi><mo>(</mo><mi>B</mi><mo>,</mo><msup><mrow><mi>C</mi></mrow><mrow><mi>n</mi></mrow></msup><mo>)</mo></math></span> of holomorphic mappings from the open Euclidean unit ball <span><math><mi>B</mi></math></span> of <span><math><msup><mrow><mi>C</mi></mrow><mrow><mi>n</mi></mrow></msup></math></span> into <span><math><msup><mrow><mi>C</mi></mrow><mrow><mi>n</mi></mrow></msup></math></span>. For complex or real linear functionals <em>ℓ</em>, our main results give representations of the form<span><span><span><math><mi>ℓ</mi><mo>(</mo><mi>f</mi><mo>)</mo><mo>=</mo><munder><mo>∫</mo><mrow><mi>K</mi></mrow></munder><mo>〈</mo><mi>f</mi><mo>(</mo><mi>z</mi><mo>)</mo><mo>,</mo><mi>z</mi><mo>〉</mo><mspace></mspace><mi>d</mi><mi>μ</mi><mo>(</mo><mi>z</mi><mo>)</mo><mo>,</mo><mspace></mspace><mi>ℓ</mi><mo>(</mo><mi>f</mi><mo>)</mo><mo>=</mo><munder><mo>∫</mo><mrow><mi>K</mi></mrow></munder><mi>Re</mi><mo>〈</mo><mi>f</mi><mo>(</mo><mi>z</mi><mo>)</mo><mo>,</mo><mi>z</mi><mo>〉</mo><mspace></mspace><mi>d</mi><mi>μ</mi><mo>(</mo><mi>z</mi><mo>)</mo><mo>,</mo></math></span></span></span> respectively, where <em>μ</em> is a complex Borel measure in the complex case or a finite signed or positive Borel measure in the real case, <span><math><mi>K</mi><mo>⊆</mo><mover><mrow><mi>B</mi></mrow><mo>‾</mo></mover></math></span> is a sphere centered at the origin, and the Hermitian inner product in <span><math><msup><mrow><mi>C</mi></mrow><mrow><mi>n</mi></mrow></msup></math></span> is denoted in the integrands. The complex representation broadly applies to closed complex subspaces of <span><math><mi>H</mi><mo>(</mo><mi>B</mi><mo>,</mo><msup><mrow><mi>C</mi></mrow><mrow><mi>n</mi></mrow></msup><mo>)</mo></math></span>, while the real versions assume various restrictions on real subspaces of <span><math><mi>H</mi><mo>(</mo><mi>B</mi><mo>,</mo><msup><mrow><mi>C</mi></mrow><mrow><mi>n</mi></mrow></msup><mo>)</mo></math></span> whose necessity is explored. Several other representations stem from the main results.</div></div>","PeriodicalId":15750,"journal":{"name":"Journal of Functional Analysis","volume":"290 6","pages":"Article 111302"},"PeriodicalIF":1.6,"publicationDate":"2025-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145734875","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 : 2025-12-08DOI: 10.1016/j.jfa.2025.111304
Tarek M. Elgindi , Milton C. Lopes Filho , Helena J. Nussenzveig Lopes
A family of solutions of the incompressible Navier-Stokes equations is said to present anomalous dissipation if energy dissipation due to viscosity does not vanish in the limit of small viscosity. In this article we present a proof of absence of anomalous dissipation for 2D flows on the torus, with an arbitrary non-negative measure plus an integrable function as initial vorticity and square-integrable initial velocity. Our result applies to flows with forcing and provides an explicit estimate for the dissipation at small viscosity. The proof relies on a new refinement of a classical inequality due to J. Nash.
{"title":"Absence of anomalous dissipation for vortex sheets","authors":"Tarek M. Elgindi , Milton C. Lopes Filho , Helena J. Nussenzveig Lopes","doi":"10.1016/j.jfa.2025.111304","DOIUrl":"10.1016/j.jfa.2025.111304","url":null,"abstract":"<div><div>A family of solutions of the incompressible Navier-Stokes equations is said to present anomalous dissipation if energy dissipation due to viscosity does not vanish in the limit of small viscosity. In this article we present a proof of absence of anomalous dissipation for 2D flows on the torus, with an arbitrary non-negative measure plus an integrable function as initial vorticity and square-integrable initial velocity. Our result applies to flows with forcing and provides an explicit estimate for the dissipation at small viscosity. The proof relies on a new refinement of a classical inequality due to J. Nash.</div></div>","PeriodicalId":15750,"journal":{"name":"Journal of Functional Analysis","volume":"290 6","pages":"Article 111304"},"PeriodicalIF":1.6,"publicationDate":"2025-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145837254","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 : 2025-12-08DOI: 10.1016/j.jfa.2025.111299
Xu Zhang , Ying Zhang , Rui Zhu
<div><div>We are concerned with clustering-peak solutions to the following stationary Hamiltonian elliptic system<span><span><span><math><mrow><mo>{</mo><mtable><mtr><mtd></mtd><mtd><mo>−</mo><msup><mrow><mi>ε</mi></mrow><mrow><mn>2</mn></mrow></msup><mi>Δ</mi><mi>u</mi><mo>+</mo><mi>V</mi><mo>(</mo><mi>x</mi><mo>)</mo><mi>u</mi><mo>=</mo><mi>g</mi><mo>(</mo><mi>v</mi><mo>)</mo><mspace></mspace><mspace></mspace><mrow><mtext>in</mtext><mspace></mspace></mrow><mspace></mspace><msup><mrow><mi>R</mi></mrow><mrow><mn>2</mn></mrow></msup><mo>,</mo></mtd></mtr><mtr><mtd></mtd><mtd><mo>−</mo><msup><mrow><mi>ε</mi></mrow><mrow><mn>2</mn></mrow></msup><mi>Δ</mi><mi>v</mi><mo>+</mo><mi>V</mi><mo>(</mo><mi>x</mi><mo>)</mo><mi>v</mi><mo>=</mo><mi>f</mi><mo>(</mo><mi>u</mi><mo>)</mo><mspace></mspace><mspace></mspace><mrow><mtext>in</mtext><mspace></mspace></mrow><mspace></mspace><msup><mrow><mi>R</mi></mrow><mrow><mn>2</mn></mrow></msup><mo>,</mo></mtd></mtr><mtr><mtd></mtd><mtd><mspace></mspace><mi>u</mi><mo>(</mo><mi>x</mi><mo>)</mo><mo>→</mo><mn>0</mn><mo>,</mo><mspace></mspace><mspace></mspace><mi>v</mi><mo>(</mo><mi>x</mi><mo>)</mo><mo>→</mo><mn>0</mn><mspace></mspace><mrow><mi>as</mi></mrow><mspace></mspace><mo>|</mo><mi>x</mi><mo>|</mo><mo>→</mo><mo>∞</mo><mo>.</mo></mtd></mtr></mtable></mrow></math></span></span></span> Here <span><math><mi>ε</mi><mo>></mo><mn>0</mn></math></span> is a small parameter, <em>V</em> has a local maximum point, and <span><math><mi>f</mi><mo>,</mo><mi>g</mi></math></span> are assumed to be of critical growth in the sense of the Trudinger–Moser inequality. Differently from most results that consider solutions for the critical equation near the ground state level <span><math><msub><mrow><mi>c</mi></mrow><mrow><mn>0</mn></mrow></msub></math></span>, we attempt to construct high-energy solutions at levels close to <span><math><mi>k</mi><msub><mrow><mi>c</mi></mrow><mrow><mn>0</mn></mrow></msub></math></span> for any integer <em>k</em>. The solutions possess <em>k</em> peaks that cluster around a local maximum of <em>V</em> as <span><math><mi>ε</mi><mo>→</mo><mn>0</mn></math></span>. Due to the critical growth of the nonlinear terms, in order to handle the compactness problem, we make uniform estimates of the exponential integral of functions in a suitable neighborhood. Since there is no non-degeneracy property for the ground state solutions of the limit system, the variational method is applied here, and a sensitive lower gradient estimate should be made when the local centroids of the functions are away from the local maximum of <em>V</em>. We introduce a new method to obtain this estimate, which differs from the ideas of Del Pino and Felmer (2002) <span><span>[27]</span></span>, and Byeon and Tanaka (2013, 2014) <span><span>[9]</span></span>, <span><span>[10]</span></span>. In addition, the fact that the energy functional corresponding to Hamiltonian elliptic systems is strongly indefinite poses additional difficulties for
我们关注以下平稳哈密顿椭圆系统{−ε2Δu+V(x)u=g(V)inR2,−ε2Δv+V(x) V =f(u)inR2,u(x)→0,V(x)→0as|x|→∞的聚类峰解。这里ε>;0是一个小参数,V有一个局部极大点,f,g在Trudinger-Moser不等式意义上被假定为临界增长。与大多数考虑临界方程在基态能级c0附近的解的结果不同,我们试图在接近kc0的能级上构造任意整数k的高能解。解具有k个峰,这些峰聚集在V的局部最大值ε→0附近。由于非线性项的临界增长,为了处理紧性问题,我们在合适的邻域内对函数的指数积分作了一致估计。由于极限系统的基态解不具有非简并性,本文采用变分方法,当函数的局部质心远离v的局部最大值时,需要进行敏感的低梯度估计。本文引入了一种不同于Del Pino and Felmer(2002)[27]和Byeon and Tanaka(2013, 2014)[9],[10]的新方法来获得这种估计。此外,哈密顿椭圆系统对应的能量泛函是强不定的,这给我们的证明带来了额外的困难。通过考虑外部区域上的辅助极大极小问题和对初始路径能量的精确估计,得到了该泛函在合适邻域内的连接结构。结合前面提到的梯度估计和应用局部变形的方法,我们得到了系统期望解的存在性。
{"title":"Clustering type solutions for critical elliptic system in dimension two","authors":"Xu Zhang , Ying Zhang , Rui Zhu","doi":"10.1016/j.jfa.2025.111299","DOIUrl":"10.1016/j.jfa.2025.111299","url":null,"abstract":"<div><div>We are concerned with clustering-peak solutions to the following stationary Hamiltonian elliptic system<span><span><span><math><mrow><mo>{</mo><mtable><mtr><mtd></mtd><mtd><mo>−</mo><msup><mrow><mi>ε</mi></mrow><mrow><mn>2</mn></mrow></msup><mi>Δ</mi><mi>u</mi><mo>+</mo><mi>V</mi><mo>(</mo><mi>x</mi><mo>)</mo><mi>u</mi><mo>=</mo><mi>g</mi><mo>(</mo><mi>v</mi><mo>)</mo><mspace></mspace><mspace></mspace><mrow><mtext>in</mtext><mspace></mspace></mrow><mspace></mspace><msup><mrow><mi>R</mi></mrow><mrow><mn>2</mn></mrow></msup><mo>,</mo></mtd></mtr><mtr><mtd></mtd><mtd><mo>−</mo><msup><mrow><mi>ε</mi></mrow><mrow><mn>2</mn></mrow></msup><mi>Δ</mi><mi>v</mi><mo>+</mo><mi>V</mi><mo>(</mo><mi>x</mi><mo>)</mo><mi>v</mi><mo>=</mo><mi>f</mi><mo>(</mo><mi>u</mi><mo>)</mo><mspace></mspace><mspace></mspace><mrow><mtext>in</mtext><mspace></mspace></mrow><mspace></mspace><msup><mrow><mi>R</mi></mrow><mrow><mn>2</mn></mrow></msup><mo>,</mo></mtd></mtr><mtr><mtd></mtd><mtd><mspace></mspace><mi>u</mi><mo>(</mo><mi>x</mi><mo>)</mo><mo>→</mo><mn>0</mn><mo>,</mo><mspace></mspace><mspace></mspace><mi>v</mi><mo>(</mo><mi>x</mi><mo>)</mo><mo>→</mo><mn>0</mn><mspace></mspace><mrow><mi>as</mi></mrow><mspace></mspace><mo>|</mo><mi>x</mi><mo>|</mo><mo>→</mo><mo>∞</mo><mo>.</mo></mtd></mtr></mtable></mrow></math></span></span></span> Here <span><math><mi>ε</mi><mo>></mo><mn>0</mn></math></span> is a small parameter, <em>V</em> has a local maximum point, and <span><math><mi>f</mi><mo>,</mo><mi>g</mi></math></span> are assumed to be of critical growth in the sense of the Trudinger–Moser inequality. Differently from most results that consider solutions for the critical equation near the ground state level <span><math><msub><mrow><mi>c</mi></mrow><mrow><mn>0</mn></mrow></msub></math></span>, we attempt to construct high-energy solutions at levels close to <span><math><mi>k</mi><msub><mrow><mi>c</mi></mrow><mrow><mn>0</mn></mrow></msub></math></span> for any integer <em>k</em>. The solutions possess <em>k</em> peaks that cluster around a local maximum of <em>V</em> as <span><math><mi>ε</mi><mo>→</mo><mn>0</mn></math></span>. Due to the critical growth of the nonlinear terms, in order to handle the compactness problem, we make uniform estimates of the exponential integral of functions in a suitable neighborhood. Since there is no non-degeneracy property for the ground state solutions of the limit system, the variational method is applied here, and a sensitive lower gradient estimate should be made when the local centroids of the functions are away from the local maximum of <em>V</em>. We introduce a new method to obtain this estimate, which differs from the ideas of Del Pino and Felmer (2002) <span><span>[27]</span></span>, and Byeon and Tanaka (2013, 2014) <span><span>[9]</span></span>, <span><span>[10]</span></span>. In addition, the fact that the energy functional corresponding to Hamiltonian elliptic systems is strongly indefinite poses additional difficulties for ","PeriodicalId":15750,"journal":{"name":"Journal of Functional Analysis","volume":"290 6","pages":"Article 111299"},"PeriodicalIF":1.6,"publicationDate":"2025-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145734879","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 : 2025-11-19DOI: 10.1016/j.jfa.2025.111285
Pritam Ganguly , Abhishek Ghosh
In this article, we establish dimension-free Fefferman-Stein inequalities for the Hardy-Littlewood maximal function associated with averages over Korányi balls in the Heisenberg group. We also generalize the result to more general UMD lattices. As a key stepping stone, we establish the - boundedness of the vector-valued Nevo-Thangavelu spherical maximal function, which plays a crucial role in our proofs of the main theorems.
{"title":"Dimension free estimates for the vector-valued Hardy–Littlewood maximal function on the Heisenberg group","authors":"Pritam Ganguly , Abhishek Ghosh","doi":"10.1016/j.jfa.2025.111285","DOIUrl":"10.1016/j.jfa.2025.111285","url":null,"abstract":"<div><div>In this article, we establish dimension-free Fefferman-Stein inequalities for the Hardy-Littlewood maximal function associated with averages over Korányi balls in the Heisenberg group. We also generalize the result to more general UMD lattices. As a key stepping stone, we establish the <span><math><msup><mrow><mi>L</mi></mrow><mrow><mi>p</mi></mrow></msup></math></span>- boundedness of the vector-valued Nevo-Thangavelu spherical maximal function, which plays a crucial role in our proofs of the main theorems.</div></div>","PeriodicalId":15750,"journal":{"name":"Journal of Functional Analysis","volume":"290 5","pages":"Article 111285"},"PeriodicalIF":1.6,"publicationDate":"2025-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145616261","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}