{"title":"Hausdorffness of certain nilpotent cohomology spaces","authors":"Fabian Januszewski , Binyong Sun , Hao Ying","doi":"10.1016/j.jfa.2025.111120","DOIUrl":"10.1016/j.jfa.2025.111120","url":null,"abstract":"<div><div>Let <span><math><mo>(</mo><mi>π</mi><mo>,</mo><mi>V</mi><mo>)</mo></math></span> be a smooth representation of a compact Lie group <em>G</em> on a quasi-complete locally convex complex topological vector space. We show that the Lie algebra cohomology space <span><math><msup><mrow><mi>H</mi></mrow><mrow><mo>•</mo></mrow></msup><mo>(</mo><mi>u</mi><mo>,</mo><mi>V</mi><mo>)</mo></math></span> and the Lie algebra homology space <span><math><msub><mrow><mi>H</mi></mrow><mrow><mo>•</mo></mrow></msub><mo>(</mo><mi>u</mi><mo>,</mo><mi>V</mi><mo>)</mo></math></span> are both Hausdorff, where <span><math><mi>u</mi></math></span> is the nilpotent radical of a parabolic subalgebra of the complexified Lie algebra <span><math><mi>g</mi></math></span> of <em>G</em>.</div></div>","PeriodicalId":15750,"journal":{"name":"Journal of Functional Analysis","volume":"289 10","pages":"Article 111120"},"PeriodicalIF":1.7,"publicationDate":"2025-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144570096","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}
{"title":"An epiperimetric inequality for odd frequencies in the thin obstacle problem","authors":"Matteo Carducci , Bozhidar Velichkov","doi":"10.1016/j.jfa.2025.111115","DOIUrl":"10.1016/j.jfa.2025.111115","url":null,"abstract":"<div><div>We prove for the first time an epiperimetric inequality for the thin obstacle Weiss' energy with odd frequencies and we apply it to solutions to the thin obstacle problem with general <span><math><msup><mrow><mi>C</mi></mrow><mrow><mi>k</mi><mo>,</mo><mi>γ</mi></mrow></msup></math></span> obstacle. In particular, we obtain the rate of convergence of the blow-up sequences at points of odd frequencies and the regularity of the strata of the corresponding contact set. We also recover the frequency gap for odd frequencies obtained by Savin and Yu.</div></div>","PeriodicalId":15750,"journal":{"name":"Journal of Functional Analysis","volume":"289 10","pages":"Article 111115"},"PeriodicalIF":1.7,"publicationDate":"2025-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144588677","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}
{"title":"Maximal amenability of the radial subalgebra in free quantum group factors","authors":"Roland Vergnioux , Xumin Wang","doi":"10.1016/j.jfa.2025.111118","DOIUrl":"10.1016/j.jfa.2025.111118","url":null,"abstract":"<div><div>We show that the radial MASA in the orthogonal free quantum group algebra <span><math><mi>L</mi><mo>(</mo><mi>F</mi><msub><mrow><mi>O</mi></mrow><mrow><mi>N</mi></mrow></msub><mo>)</mo></math></span> is maximal amenable if <em>N</em> is large enough, using the Asymptotic Orthogonality Property. This relies on a detailed study of the corresponding bimodule, for which we construct in particular a quantum analogue of Rădulescu's basis. As a byproduct we also obtain the value of the Pukánszky invariant for this MASA.</div></div>","PeriodicalId":15750,"journal":{"name":"Journal of Functional Analysis","volume":"289 10","pages":"Article 111118"},"PeriodicalIF":1.7,"publicationDate":"2025-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144588678","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}
{"title":"Time periodic and almost periodic viscosity solutions of contact Hamilton-Jacobi equations on Tn","authors":"Kaizhi Wang , Jun Yan , Kai Zhao","doi":"10.1016/j.jfa.2025.111121","DOIUrl":"10.1016/j.jfa.2025.111121","url":null,"abstract":"<div><div>This paper concerns with the time periodic viscosity solution problem for a class of evolutionary contact Hamilton-Jacobi equations with time independent Hamiltonians on the torus <span><math><msup><mrow><mi>T</mi></mrow><mrow><mi>n</mi></mrow></msup></math></span>. Under certain suitable assumptions we show that the equation has a non-trivial <em>T</em>-periodic viscosity solution if and only if <span><math><mi>T</mi><mo>∈</mo><mi>D</mi></math></span>, where <em>D</em> is a dense subset of <span><math><mo>[</mo><mn>0</mn><mo>,</mo><mo>+</mo><mo>∞</mo><mo>)</mo></math></span>. Moreover, we clarify the structure of <em>D</em>. As a consequence, we also study the existence of Bohr almost periodic viscosity solutions.</div></div>","PeriodicalId":15750,"journal":{"name":"Journal of Functional Analysis","volume":"289 10","pages":"Article 111121"},"PeriodicalIF":1.7,"publicationDate":"2025-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144570099","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}
{"title":"Limit formulas for norms of tensor power operators","authors":"Guillaume Aubrun , Alexander Müller-Hermes","doi":"10.1016/j.jfa.2025.111113","DOIUrl":"10.1016/j.jfa.2025.111113","url":null,"abstract":"<div><div>Given an operator <span><math><mi>ϕ</mi><mo>:</mo><mi>X</mi><mo>→</mo><mi>Y</mi></math></span> between Banach spaces, we consider its tensor powers <span><math><msup><mrow><mi>ϕ</mi></mrow><mrow><mo>⊗</mo><mi>k</mi></mrow></msup></math></span> as operators from the <em>k</em>-fold injective tensor product of <em>X</em> to the <em>k</em>-fold projective tensor product of <em>Y</em>. We show that after taking the <em>k</em>th root, the operator norm of <span><math><msup><mrow><mi>ϕ</mi></mrow><mrow><mo>⊗</mo><mi>k</mi></mrow></msup></math></span> converges to the 2-dominated norm <span><math><msubsup><mrow><mi>γ</mi></mrow><mrow><mn>2</mn></mrow><mrow><mo>⁎</mo></mrow></msubsup><mo>(</mo><mi>ϕ</mi><mo>)</mo></math></span>, one of the standard operator ideal norms.</div></div>","PeriodicalId":15750,"journal":{"name":"Journal of Functional Analysis","volume":"289 10","pages":"Article 111113"},"PeriodicalIF":1.7,"publicationDate":"2025-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144570097","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}
{"title":"The spectral gap of a Gaussian quantum Markovian generator","authors":"F. Fagnola, D. Poletti, E. Sasso, V. Umanità","doi":"10.1016/j.jfa.2025.111119","DOIUrl":"10.1016/j.jfa.2025.111119","url":null,"abstract":"<div><div>Gaussian quantum Markov semigroups are the natural non-commutative extension of classical Ornstein-Uhlenbeck semigroups. They arise in open quantum systems of bosons where canonical non-commuting random variables of positions and momenta come into play. If there exists a faithful invariant density we explicitly compute the optimal exponential convergence rate, namely the spectral gap of the generator, in non-commutative <span><math><msup><mrow><mi>L</mi></mrow><mrow><mn>2</mn></mrow></msup></math></span> spaces determined by the invariant density showing that the exact value is the lowest eigenvalue of a certain matrix determined by the diffusion and drift matrices. The spectral gap turns out to depend on the non-commutative <span><math><msup><mrow><mi>L</mi></mrow><mrow><mn>2</mn></mrow></msup></math></span> space considered, whether the one determined by the so-called GNS or KMS multiplication by the square root of the invariant density. In the first case, it is strictly positive if and only if there is the maximum number of linearly independent noises. While, we exhibit explicit examples in which it is strictly positive only with KMS multiplication. We do not assume any symmetry or quantum detailed balance condition with respect to the invariant density.</div></div>","PeriodicalId":15750,"journal":{"name":"Journal of Functional Analysis","volume":"289 10","pages":"Article 111119"},"PeriodicalIF":1.7,"publicationDate":"2025-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144579253","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}
Hugo Aimar , Ivana Gómez , Ignacio Gómez Vargas , Francisco Javier Martín-Reyes
{"title":"One-sided Muckenhoupt weights and one-sided weakly porous sets in R","authors":"Hugo Aimar , Ivana Gómez , Ignacio Gómez Vargas , Francisco Javier Martín-Reyes","doi":"10.1016/j.jfa.2025.111110","DOIUrl":"10.1016/j.jfa.2025.111110","url":null,"abstract":"<div><div>In this work, we introduce the geometric concept of one-sided weakly porous sets in the real line and show that a set <span><math><mi>E</mi><mo>⊂</mo><mi>R</mi></math></span> satisfies <span><math><mi>d</mi><msup><mrow><mo>(</mo><mo>⋅</mo><mo>,</mo><mi>E</mi><mo>)</mo></mrow><mrow><mo>−</mo><mi>α</mi></mrow></msup><mo>∈</mo><msubsup><mrow><mi>A</mi></mrow><mrow><mn>1</mn></mrow><mrow><mo>+</mo></mrow></msubsup><mo>(</mo><mi>R</mi><mo>)</mo><mo>∩</mo><msubsup><mrow><mi>L</mi></mrow><mrow><mtext>loc</mtext></mrow><mrow><mn>1</mn></mrow></msubsup><mo>(</mo><mi>R</mi><mo>)</mo></math></span> for some <span><math><mi>α</mi><mo>></mo><mn>0</mn></math></span> if and only if <em>E</em> is right-sided weakly porous. Furthermore, we find that the property of being both left-sided and right-sided weakly porous is equivalent to the recent weakly porous condition discussed in the bibliography, which, in turn, was previously found to be intimately related to the usual class of Muckenhoupt weights <span><math><msub><mrow><mi>A</mi></mrow><mrow><mn>1</mn></mrow></msub></math></span>.</div></div>","PeriodicalId":15750,"journal":{"name":"Journal of Functional Analysis","volume":"289 10","pages":"Article 111110"},"PeriodicalIF":1.7,"publicationDate":"2025-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144579254","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}
{"title":"Random geometric graphs in reflexive Banach spaces","authors":"József Balogh , Mark Walters , András Zsák","doi":"10.1016/j.jfa.2025.111112","DOIUrl":"10.1016/j.jfa.2025.111112","url":null,"abstract":"<div><div>We investigate a random geometric graph model introduced by Bonato and Janssen. The vertices are the points of a countable dense set <em>S</em> in a (necessarily separable) normed vector space <em>X</em>, and each pair of points are joined independently with some fixed probability <em>p</em> (with <span><math><mn>0</mn><mo><</mo><mi>p</mi><mo><</mo><mn>1</mn></math></span>) if they are less than distance 1 apart. A countable dense set <em>S</em> in a normed space is <em>Rado</em>, if the resulting graph is almost surely unique up to isomorphism: that is any two such graphs are, almost surely, isomorphic.</div><div>Not surprisingly, understanding which sets are Rado is closely related to the geometry of the underlying normed space. It turns out that a key question is in which spaces must step-isometries (maps that preserve the integer parts of distances) on dense subsets necessarily be isometries. We answer this question for a large class of Banach spaces including all strictly convex reflexive spaces. In the process we prove results on the interplay between the norm topology and weak topology that may be of independent interest.</div><div>As a consequence of these Banach space results we show that almost all countable dense sets in strictly convex reflexive spaces are strongly non-Rado (that is, any two graphs are almost surely non-isomorphic). However, we show that there do exist Rado sets even in <span><math><msub><mrow><mi>ℓ</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span>. Finally we construct a Banach space in which all countable dense set are strongly non-Rado.</div></div>","PeriodicalId":15750,"journal":{"name":"Journal of Functional Analysis","volume":"289 11","pages":"Article 111112"},"PeriodicalIF":1.7,"publicationDate":"2025-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144588591","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}
Serena Dipierro , João Gonçalves da Silva , Giorgio Poggesi , Enrico Valdinoci
{"title":"A quantitative Gidas-Ni-Nirenberg-type result for the p-Laplacian via integral identities","authors":"Serena Dipierro , João Gonçalves da Silva , Giorgio Poggesi , Enrico Valdinoci","doi":"10.1016/j.jfa.2025.111108","DOIUrl":"10.1016/j.jfa.2025.111108","url":null,"abstract":"<div><div>We prove a quantitative version of a Gidas-Ni-Nirenberg-type symmetry result involving the <em>p</em>-Laplacian.</div><div>Quantitative stability is achieved here via integral identities based on the proof of rigidity established by J. Serra in 2013, which extended to general dimension and the <em>p</em>-Laplacian operator an argument proposed by P.-L. Lions in dimension 2 for the classical Laplacian.</div><div>Stability results for the classical Gidas-Ni-Nirenberg symmetry theorem (involving the classical Laplacian) via the method of moving planes were established by Rosset in 1994 and by Ciraolo, Cozzi, Perugini, Pollastro in 2024.</div><div>To the authors' knowledge, the present paper provides the first quantitative Gidas-Ni-Nirenberg-type result involving the <em>p</em>-Laplacian for <span><math><mi>p</mi><mo>≠</mo><mn>2</mn></math></span>. Even for the classical Laplacian (i.e., for <span><math><mi>p</mi><mo>=</mo><mn>2</mn></math></span>), this is the first time that integral identities are used to achieve stability for a Gidas-Ni-Nirenberg-type result.</div><div>In passing, we obtain a quantitative estimate for the measure of the singular set and an explicit uniform gradient bound.</div></div>","PeriodicalId":15750,"journal":{"name":"Journal of Functional Analysis","volume":"289 10","pages":"Article 111108"},"PeriodicalIF":1.7,"publicationDate":"2025-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144536014","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}
{"title":"Anderson localization for CMV matrices with Verblunsky coefficients defined by the hyperbolic toral automorphism","authors":"Yanxue Lin , Shuzheng Guo , Daxiong Piao","doi":"10.1016/j.jfa.2025.111103","DOIUrl":"10.1016/j.jfa.2025.111103","url":null,"abstract":"<div><div>In this paper, we prove the large deviation estimates and Anderson localization for CMV matrices on <span><math><msup><mrow><mi>ℓ</mi></mrow><mrow><mn>2</mn></mrow></msup><mo>(</mo><msub><mrow><mi>Z</mi></mrow><mrow><mo>+</mo></mrow></msub><mo>)</mo></math></span> with Verblunsky coefficients defined dynamically by the hyperbolic toral automorphism. Part of positivity results on the Lyapunov exponents of Chulaevsky-Spencer <span><span>[9]</span></span> and Anderson localization results of Bourgain-Schlag <span><span>[6]</span></span> on Schrödinger operators with strongly mixing potentials are extended to CMV matrices.</div></div>","PeriodicalId":15750,"journal":{"name":"Journal of Functional Analysis","volume":"289 9","pages":"Article 111103"},"PeriodicalIF":1.7,"publicationDate":"2025-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144489470","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}