{"title":"On the lack of selection for the transport equation over a dense set of vector fields","authors":"Jules Pitcho","doi":"10.1016/j.jfa.2025.110942","DOIUrl":"10.1016/j.jfa.2025.110942","url":null,"abstract":"<div><div>We construct a set of bounded vector fields dense in <span><math><msup><mrow><mi>L</mi></mrow><mrow><mi>p</mi></mrow></msup><mo>(</mo><mo>(</mo><mn>0</mn><mo>,</mo><mn>2</mn><mo>)</mo><mo>;</mo><msubsup><mrow><mi>W</mi></mrow><mrow><mi>l</mi><mi>o</mi><mi>c</mi></mrow><mrow><mi>s</mi><mo>,</mo><mi>p</mi></mrow></msubsup><mo>(</mo><msup><mrow><mi>R</mi></mrow><mrow><mi>d</mi></mrow></msup><mo>;</mo><msup><mrow><mi>R</mi></mrow><mrow><mi>d</mi></mrow></msup><mo>)</mo><mo>)</mo></math></span> for <span><math><mn>1</mn><mo>≤</mo><mi>p</mi><mo><</mo><mo>+</mo><mo>∞</mo></math></span> and <span><math><mn>0</mn><mo>≤</mo><mi>s</mi><mo><</mo><mn>1</mn></math></span> with <span><math><mi>p</mi><mo><</mo><mn>1</mn><mo>/</mo><mi>s</mi></math></span> for which smooth regularisation of the vector field does not give a selection criterion for the continuity equation, thereby showing that the two examples constructed in <span><span>[10]</span></span>, <span><span>[12]</span></span> are generic.</div></div>","PeriodicalId":15750,"journal":{"name":"Journal of Functional Analysis","volume":"289 6","pages":"Article 110942"},"PeriodicalIF":1.7,"publicationDate":"2025-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143786172","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Classical solutions to the thin-film equation with general mobility in the perfect-wetting regime","authors":"Manuel V. Gnann, Anouk C. Wisse","doi":"10.1016/j.jfa.2025.110941","DOIUrl":"10.1016/j.jfa.2025.110941","url":null,"abstract":"<div><div>We prove well-posedness, partial regularity, and stability of the thin-film equation <span><math><msub><mrow><mi>h</mi></mrow><mrow><mi>t</mi></mrow></msub><mo>+</mo><msub><mrow><mo>(</mo><mi>m</mi><mo>(</mo><mi>h</mi><mo>)</mo><msub><mrow><mi>h</mi></mrow><mrow><mi>z</mi><mi>z</mi><mi>z</mi></mrow></msub><mo>)</mo></mrow><mrow><mi>z</mi></mrow></msub><mo>=</mo><mn>0</mn></math></span> with general mobility <span><math><mi>m</mi><mo>(</mo><mi>h</mi><mo>)</mo><mo>=</mo><msup><mrow><mi>h</mi></mrow><mrow><mi>n</mi></mrow></msup></math></span> and mobility exponent <span><math><mi>n</mi><mo>∈</mo><mo>(</mo><mn>1</mn><mo>,</mo><mfrac><mrow><mn>3</mn></mrow><mrow><mn>2</mn></mrow></mfrac><mo>)</mo><mo>∪</mo><mo>(</mo><mfrac><mrow><mn>3</mn></mrow><mrow><mn>2</mn></mrow></mfrac><mo>,</mo><mn>3</mn><mo>)</mo></math></span> in the regime of perfect wetting (zero contact angle). After a suitable coordinate transformation to fix the free boundary (the contact line where liquid, air, and solid coalesce), the thin-film equation is rewritten as an abstract Cauchy problem and we obtain maximal <span><math><msubsup><mrow><mi>L</mi></mrow><mrow><mi>t</mi></mrow><mrow><mi>p</mi></mrow></msubsup></math></span>-regularity for the linearized evolution. Partial regularity close to the free boundary is obtained by studying the elliptic regularity of the spatial part of the linearization. This yields solutions that are non-smooth in the distance to the free boundary, in line with previous findings for source-type self-similar solutions. In a scaling-wise quasi-minimal norm for the initial data, we obtain a well-posedness and asymptotic stability result for perturbations of traveling waves. The novelty of this work lies in the usage of <span><math><msup><mrow><mi>L</mi></mrow><mrow><mi>p</mi></mrow></msup></math></span>-estimates in time, where <span><math><mn>1</mn><mo><</mo><mi>p</mi><mo><</mo><mo>∞</mo></math></span>, while the existing literature mostly deals with <span><math><mi>p</mi><mo>=</mo><mn>2</mn></math></span> at least for nonlinear mobilities. This turns out to be essential to obtain for the first time a well-posedness result in the perfect-wetting regime for all physical nonlinear slip conditions except for a strongly degenerate case at <span><math><mi>n</mi><mo>=</mo><mfrac><mrow><mn>3</mn></mrow><mrow><mn>2</mn></mrow></mfrac></math></span> and the well-understood Greenspan-slip case <span><math><mi>n</mi><mo>=</mo><mn>1</mn></math></span>. Furthermore, compared to <span><span>[36]</span></span> by Giacomelli, the first author of this paper, Knüpfer, and Otto, where a PDE approach yields <span><math><msubsup><mrow><mi>L</mi></mrow><mrow><mi>t</mi></mrow><mrow><mn>2</mn></mrow></msubsup></math></span>-estimates, well-posedness, and stability for <span><math><mn>1.8384</mn><mo>≈</mo><mfrac><mrow><mn>3</mn></mrow><mrow><mn>17</mn></mrow></mfrac><mo>(</mo><mn>15</mn><mo>−</mo><msqrt><mrow><mn>21</mn></mrow></msqrt><mo>)</mo><mo><</mo><mi","PeriodicalId":15750,"journal":{"name":"Journal of Functional Analysis","volume":"289 8","pages":"Article 110941"},"PeriodicalIF":1.7,"publicationDate":"2025-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143837981","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":"A weighted decoupling inequality and its application to the maximal Bochner-Riesz problem","authors":"Shengwen Gan , Shukun Wu","doi":"10.1016/j.jfa.2025.110943","DOIUrl":"10.1016/j.jfa.2025.110943","url":null,"abstract":"<div><div>We prove some weighted <span><math><msup><mrow><mi>L</mi></mrow><mrow><mi>p</mi></mrow></msup><msup><mrow><mi>ℓ</mi></mrow><mrow><mi>p</mi></mrow></msup></math></span>-decoupling estimates when <span><math><mi>p</mi><mo>=</mo><mn>2</mn><mi>n</mi><mo>/</mo><mo>(</mo><mi>n</mi><mo>−</mo><mn>1</mn><mo>)</mo></math></span>. As an application, we give a result beyond the real interpolation exponents for the maximal Bochner-Riesz operator in <span><math><msup><mrow><mi>R</mi></mrow><mrow><mn>3</mn></mrow></msup></math></span>. We also make an improvement in the planar case.</div></div>","PeriodicalId":15750,"journal":{"name":"Journal of Functional Analysis","volume":"289 3","pages":"Article 110943"},"PeriodicalIF":1.7,"publicationDate":"2025-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143685943","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}
Giovanni Bellettini , Alaa Elshorbagy , Riccardo Scala
{"title":"Relaxation of the area of the vortex map: A non-parametric Plateau problem for a catenoid containing a segment","authors":"Giovanni Bellettini , Alaa Elshorbagy , Riccardo Scala","doi":"10.1016/j.jfa.2025.110947","DOIUrl":"10.1016/j.jfa.2025.110947","url":null,"abstract":"<div><div>Motivated by the study of the non-parametric area <span><math><mi>A</mi></math></span> of the graph of the vortex map <em>u</em> (a two-codimensional singular surface in <span><math><msup><mrow><mi>R</mi></mrow><mrow><mn>4</mn></mrow></msup></math></span>) over the disk <span><math><mi>Ω</mi><mo>⊂</mo><msup><mrow><mi>R</mi></mrow><mrow><mn>2</mn></mrow></msup></math></span> of radius <em>l</em>, we perform a careful analysis of the singular part of the relaxation of <span><math><mi>A</mi></math></span> computed at <em>u</em>. The precise description is given in terms of an area-minimizing surface in a vertical copy of <span><math><msup><mrow><mi>R</mi></mrow><mrow><mn>3</mn></mrow></msup><mo>⊂</mo><msup><mrow><mi>R</mi></mrow><mrow><mn>4</mn></mrow></msup></math></span>, which is a sort of “catenoid” containing a segment corresponding to a radius of Ω. The problem involves an area-minimization with a free boundary part; several boundary regularity properties of the minimizer are inspected.</div></div>","PeriodicalId":15750,"journal":{"name":"Journal of Functional Analysis","volume":"289 5","pages":"Article 110947"},"PeriodicalIF":1.7,"publicationDate":"2025-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143748536","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Andrea Pinamonti, Francesco Serra Cassano, Kilian Zambanini
{"title":"On some intrinsic differentiability properties for absolutely continuous functions between Carnot groups and the area formula","authors":"Andrea Pinamonti, Francesco Serra Cassano, Kilian Zambanini","doi":"10.1016/j.jfa.2025.110948","DOIUrl":"10.1016/j.jfa.2025.110948","url":null,"abstract":"<div><div>We discuss <em>Q</em>-absolutely continuous functions between Carnot groups, following Malý's definition for maps of several variables (<span><span>[43]</span></span>). Such maps enjoy nice regularity properties, like continuity, Pansu differentiability a.e., weak differentiability and an area formula. Furthermore, we extend Stein's result concerning the sharp condition for continuity and differentiability a.e. of a Sobolev map in terms of the integrability of the weak gradient: more precisely, we prove that a Sobolev map between Carnot groups with horizontal gradient of its sections uniformly bounded in <span><math><msup><mrow><mi>L</mi></mrow><mrow><mi>Q</mi><mo>,</mo><mn>1</mn></mrow></msup></math></span> admits a representative which is <em>Q</em>-absolutely continuous.</div></div>","PeriodicalId":15750,"journal":{"name":"Journal of Functional Analysis","volume":"289 3","pages":"Article 110948"},"PeriodicalIF":1.7,"publicationDate":"2025-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143685944","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Potential theory of Dirichlet forms with jump kernels blowing up at the boundary","authors":"Panki Kim , Renming Song , Zoran Vondraček","doi":"10.1016/j.jfa.2025.110934","DOIUrl":"10.1016/j.jfa.2025.110934","url":null,"abstract":"<div><div>In this paper we study the potential theory of Dirichlet forms on the half-space <span><math><msubsup><mrow><mi>R</mi></mrow><mrow><mo>+</mo></mrow><mrow><mi>d</mi></mrow></msubsup></math></span> defined by the jump kernel <span><math><mi>J</mi><mo>(</mo><mi>x</mi><mo>,</mo><mi>y</mi><mo>)</mo><mo>=</mo><mo>|</mo><mi>x</mi><mo>−</mo><mi>y</mi><msup><mrow><mo>|</mo></mrow><mrow><mo>−</mo><mi>d</mi><mo>−</mo><mi>α</mi></mrow></msup><mi>B</mi><mo>(</mo><mi>x</mi><mo>,</mo><mi>y</mi><mo>)</mo></math></span> and the killing potential <span><math><mi>κ</mi><msubsup><mrow><mi>x</mi></mrow><mrow><mi>d</mi></mrow><mrow><mo>−</mo><mi>α</mi></mrow></msubsup></math></span>, where <span><math><mi>α</mi><mo>∈</mo><mo>(</mo><mn>0</mn><mo>,</mo><mn>2</mn><mo>)</mo></math></span> and <span><math><mi>B</mi><mo>(</mo><mi>x</mi><mo>,</mo><mi>y</mi><mo>)</mo></math></span> can blow up to infinity at the boundary. The jump kernel and the killing potential depend on several parameters. For all admissible values of the parameters involved and all <span><math><mi>d</mi><mo>≥</mo><mn>1</mn></math></span>, we prove that the boundary Harnack principle holds, and establish sharp two-sided estimates on the Green functions of these processes.</div></div>","PeriodicalId":15750,"journal":{"name":"Journal of Functional Analysis","volume":"289 4","pages":"Article 110934"},"PeriodicalIF":1.7,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143759330","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Isoperimetric problem and structure at infinity on Alexandrov spaces with nonnegative curvature","authors":"Gioacchino Antonelli , Marco Pozzetta","doi":"10.1016/j.jfa.2025.110940","DOIUrl":"10.1016/j.jfa.2025.110940","url":null,"abstract":"<div><div>In this paper we consider nonnegatively curved finite dimensional Alexandrov spaces with a non-collapsing condition, i.e., such that unit balls have volumes uniformly bounded from below away from zero. We study the relation between the isoperimetric profile, the existence of isoperimetric sets, and the asymptotic structure at infinity of such spaces.</div><div>In this setting, we prove that the following conditions are equivalent: the space has linear volume growth; it is Gromov–Hausdorff asymptotic to one cylinder at infinity; it has uniformly bounded isoperimetric profile; the entire space is a tubular neighborhood of either a line or a ray.</div><div>Moreover, on a space satisfying any of the previous conditions, we prove existence of isoperimetric sets for sufficiently large volumes, and we characterize the geometric rigidity at the level of the isoperimetric profile.</div><div>Specializing our study to the 2-dimensional case, we prove that unit balls have always volumes uniformly bounded from below away from zero, and we prove existence of isoperimetric sets for every volume, characterizing also their topology when the space has no boundary.</div><div>The proofs exploit a variational approach, and in particular apply to Riemannian manifolds with nonnegative sectional curvature and to Euclidean convex bodies. Up to the authors' knowledge, most of the results are new even in these smooth cases.</div></div>","PeriodicalId":15750,"journal":{"name":"Journal of Functional Analysis","volume":"289 4","pages":"Article 110940"},"PeriodicalIF":1.7,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143737988","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":"Diagonals of self-adjoint operators I: Compact operators","authors":"Marcin Bownik , John Jasper","doi":"10.1016/j.jfa.2025.110939","DOIUrl":"10.1016/j.jfa.2025.110939","url":null,"abstract":"<div><div>Given a self-adjoint operator <em>T</em> on a separable infinite-dimensional Hilbert space we study the problem of characterizing the set <span><math><mi>D</mi><mo>(</mo><mi>T</mi><mo>)</mo></math></span> of all possible diagonals of <em>T</em>. For compact operators <em>T</em>, we give a complete characterization of diagonals modulo the kernel of <em>T</em>. That is, we characterize <span><math><mi>D</mi><mo>(</mo><mi>T</mi><mo>)</mo></math></span> for the class of operators sharing the same nonzero eigenvalues (with multiplicities) as <em>T</em>. Moreover, we determine <span><math><mi>D</mi><mo>(</mo><mi>T</mi><mo>)</mo></math></span> for a fixed compact operator <em>T</em>, modulo the kernel problem for positive compact operators with finite-dimensional kernel.</div><div>Our results generalize a characterization of diagonals of trace class positive operators by Arveson and Kadison <span><span>[5]</span></span> and diagonals of compact positive operators by Kaftal and Weiss <span><span>[24]</span></span> and Loreaux and Weiss <span><span>[28]</span></span>. The proof uses the technique of diagonal-to-diagonal results, which was pioneered in the earlier joint work of the authors with Siudeja <span><span>[12]</span></span>.</div></div>","PeriodicalId":15750,"journal":{"name":"Journal of Functional Analysis","volume":"289 5","pages":"Article 110939"},"PeriodicalIF":1.7,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143738470","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}
Franziska Borer , Marcos T.O. Pimenta , Patrick Winkert
{"title":"Degenerate Kirchhoff problems with nonlinear Neumann boundary condition","authors":"Franziska Borer , Marcos T.O. Pimenta , Patrick Winkert","doi":"10.1016/j.jfa.2025.110933","DOIUrl":"10.1016/j.jfa.2025.110933","url":null,"abstract":"<div><div>In this paper we consider degenerate Kirchhoff-type equations of the form<span><span><span><math><mo>−</mo><mi>ϕ</mi><mo>(</mo><mi>Ξ</mi><mo>(</mo><mi>u</mi><mo>)</mo><mo>)</mo><mrow><mo>(</mo><mi>A</mi><mo>(</mo><mi>u</mi><mo>)</mo><mo>−</mo><mo>|</mo><mi>u</mi><msup><mrow><mo>|</mo></mrow><mrow><mi>p</mi><mo>−</mo><mn>2</mn></mrow></msup><mi>u</mi><mo>)</mo></mrow><mo>=</mo><mi>f</mi><mo>(</mo><mi>x</mi><mo>,</mo><mi>u</mi><mo>)</mo><mspace></mspace><mspace></mspace><mtext>in </mtext><mi>Ω</mi><mo>,</mo><mi>ϕ</mi><mo>(</mo><mi>Ξ</mi><mo>(</mo><mi>u</mi><mo>)</mo><mo>)</mo><mi>B</mi><mo>(</mo><mi>u</mi><mo>)</mo><mo>⋅</mo><mi>ν</mi><mo>=</mo><mi>g</mi><mo>(</mo><mi>x</mi><mo>,</mo><mi>u</mi><mo>)</mo><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>, <span><math><mi>N</mi><mo>≥</mo><mn>2</mn></math></span>, is a bounded domain with Lipschitz boundary ∂Ω, <span><math><mi>A</mi></math></span> denotes the double phase operator given by<span><span><span><math><mrow><mi>A</mi><mo>(</mo><mi>u</mi><mo>)</mo><mo>=</mo><mi>div</mi><mspace></mspace><mrow><mo>(</mo><mo>|</mo><mi>∇</mi><mi>u</mi><msup><mrow><mo>|</mo></mrow><mrow><mi>p</mi><mo>−</mo><mn>2</mn></mrow></msup><mi>∇</mi><mi>u</mi><mo>+</mo><mi>μ</mi><mo>(</mo><mi>x</mi><mo>)</mo><mo>|</mo><mi>∇</mi><mi>u</mi><msup><mrow><mo>|</mo></mrow><mrow><mi>q</mi><mo>−</mo><mn>2</mn></mrow></msup><mi>∇</mi><mi>u</mi><mo>)</mo></mrow></mrow></math></span></span></span> for <span><math><mi>u</mi><mo>∈</mo><msup><mrow><mi>W</mi></mrow><mrow><mn>1</mn><mo>,</mo><mi>H</mi></mrow></msup><mo>(</mo><mi>Ω</mi><mo>)</mo></math></span>, <span><math><mi>ν</mi><mo>(</mo><mi>x</mi><mo>)</mo></math></span> is the outer unit normal of Ω at <span><math><mi>x</mi><mo>∈</mo><mo>∂</mo><mi>Ω</mi></math></span>,<span><span><span><math><mi>B</mi><mo>(</mo><mi>u</mi><mo>)</mo><mo>=</mo><mo>|</mo><mi>∇</mi><mi>u</mi><msup><mrow><mo>|</mo></mrow><mrow><mi>p</mi><mo>−</mo><mn>2</mn></mrow></msup><mi>∇</mi><mi>u</mi><mo>+</mo><mi>μ</mi><mo>(</mo><mi>x</mi><mo>)</mo><mo>|</mo><mi>∇</mi><mi>u</mi><msup><mrow><mo>|</mo></mrow><mrow><mi>q</mi><mo>−</mo><mn>2</mn></mrow></msup><mi>∇</mi><mi>u</mi><mo>,</mo><mi>Ξ</mi><mo>(</mo><mi>u</mi><mo>)</mo><mo>=</mo><munder><mo>∫</mo><mrow><mi>Ω</mi></mrow></munder><mrow><mo>(</mo><mfrac><mrow><mo>|</mo><mi>∇</mi><mi>u</mi><msup><mrow><mo>|</mo></mrow><mrow><mi>p</mi></mrow></msup><mo>+</mo><mo>|</mo><mi>u</mi><msup><mrow><mo>|</mo></mrow><mrow><mi>p</mi></mrow></msup></mrow><mrow><mi>p</mi></mrow></mfrac><mo>+</mo><mi>μ</mi><mo>(</mo><mi>x</mi><mo>)</mo><mfrac><mrow><mo>|</mo><mi>∇</mi><mi>u</mi><msup><mrow><mo>|</mo></mrow><mrow><mi>q</mi></mrow></msup></mrow><mrow><mi>q</mi></mrow></mfrac><mo>)</mo></mrow><mspace></mspace><mi>d</mi><mi>x</mi><mo>,</mo></math></span></span></span> <span><math><mn>1</mn><mo><</mo><mi>p</mi><mo><","PeriodicalId":15750,"journal":{"name":"Journal of Functional Analysis","volume":"289 4","pages":"Article 110933"},"PeriodicalIF":1.7,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143768202","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Murray–von Neumann dimension for strictly semifinite weights","authors":"Aldo Garcia Guinto, Matthew Lorentz, Brent Nelson","doi":"10.1016/j.jfa.2025.110938","DOIUrl":"10.1016/j.jfa.2025.110938","url":null,"abstract":"<div><div>Given a von Neumann algebra <em>M</em> equipped with a faithful normal strictly semifinite weight <em>φ</em>, we develop a notion of Murray–von Neumann dimension over <span><math><mo>(</mo><mi>M</mi><mo>,</mo><mi>φ</mi><mo>)</mo></math></span> that is defined for modules over the basic construction associated to the inclusion <span><math><msup><mrow><mi>M</mi></mrow><mrow><mi>φ</mi></mrow></msup><mo>⊂</mo><mi>M</mi></math></span>. For <span><math><mi>φ</mi><mo>=</mo><mi>τ</mi></math></span> a faithful normal tracial state, this recovers the usual Murray–von Neumann dimension for finite von Neumann algebras. If <em>M</em> is either a type <span><math><msub><mrow><mi>III</mi></mrow><mrow><mi>λ</mi></mrow></msub></math></span> factor with <span><math><mn>0</mn><mo><</mo><mi>λ</mi><mo><</mo><mn>1</mn></math></span> or a full type <span><math><msub><mrow><mi>III</mi></mrow><mrow><mn>1</mn></mrow></msub></math></span> factor with <span><math><mi>Sd</mi><mo>(</mo><mi>M</mi><mo>)</mo><mo>≠</mo><mi>R</mi></math></span>, then amongst extremal almost periodic weights the dimension function depends on <em>φ</em> only up to scaling. As an application, we show that if an inclusion of diffuse factors with separable preduals <span><math><mi>N</mi><mo>⊂</mo><mi>M</mi></math></span> is with expectation <span><math><mi>E</mi></math></span> and admits a compatible extremal almost periodic state <em>φ</em>, then this dimension quantity bounds the index <span><math><mi>Ind</mi><mspace></mspace><mi>E</mi></math></span>, and in fact equals it when the modular operators <span><math><msub><mrow><mi>Δ</mi></mrow><mrow><mi>φ</mi></mrow></msub></math></span> and <span><math><msub><mrow><mi>Δ</mi></mrow><mrow><mi>φ</mi><msub><mrow><mo>|</mo></mrow><mrow><mi>N</mi></mrow></msub></mrow></msub></math></span> have the same point spectrum. In the pursuit of this result, we also show such inclusions always admit Pimsner–Popa orthogonal bases.</div></div>","PeriodicalId":15750,"journal":{"name":"Journal of Functional Analysis","volume":"289 5","pages":"Article 110938"},"PeriodicalIF":1.7,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143738469","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}