{"title":"Multicomplexes on Carnot Groups and Their Associated Spectral Sequence.","authors":"Antonio Lerario, Francesca Tripaldi","doi":"10.1007/s12220-023-01259-0","DOIUrl":"https://doi.org/10.1007/s12220-023-01259-0","url":null,"abstract":"<p><p>The aim of this paper is to give a thorough insight into the relationship between the Rumin complex on Carnot groups and the spectral sequence obtained from the filtration on forms by homogeneous weights that computes the de Rham cohomology of the underlying group.</p>","PeriodicalId":56121,"journal":{"name":"Journal of Geometric Analysis","volume":"33 7","pages":"199"},"PeriodicalIF":1.1,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10119276/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9389909","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}
Phillip Baumann, Idriss Mazari-Fouquer, Kevin Sturm
{"title":"The Topological State Derivative: An Optimal Control Perspective on Topology Optimisation.","authors":"Phillip Baumann, Idriss Mazari-Fouquer, Kevin Sturm","doi":"10.1007/s12220-023-01295-w","DOIUrl":"10.1007/s12220-023-01295-w","url":null,"abstract":"<p><p>In this paper, we introduce the topological state derivative for general topological dilatations and explore its relation to standard optimal control theory. We show that for a class of partial differential equations, the shape-dependent state variable can be differentiated with respect to the topology, thus leading to a linearised system resembling those occurring in standard optimal control problems. However, a lot of care has to be taken when handling the regularity of the solutions of this linearised system. In fact, we should expect different notions of (very) weak solutions, depending on whether the main part of the operator or its lower order terms are being perturbed. We also study the relationship with the topological state derivative, usually obtained through classical topological expansions involving boundary layer correctors. A feature of the topological state derivative is that it can either be derived via Stampacchia-type regularity estimates or alternately with classical asymptotic expansions. It should be noted that our approach is flexible enough to cover more than the usual case of point perturbations of the domain. In particular, and in the line of (Delfour in SIAM J Control Optim 60(1):22-47, 2022; J Convex Anal 25(3):957-982, 2018), we deal with more general dilatations of shapes, thereby yielding topological derivatives with respect to curves, surfaces or hypersurfaces. To draw the connection to usual topological derivatives, which are typically expressed with an adjoint equation, we show how usual first-order topological derivatives of shape functionals can be easily computed using the topological state derivative.</p>","PeriodicalId":56121,"journal":{"name":"Journal of Geometric Analysis","volume":"33 8","pages":"243"},"PeriodicalIF":1.1,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10185627/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9544949","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":"Szegő Kernel Asymptotics on Complete Strictly Pseudoconvex CR Manifolds.","authors":"Chin-Yu Hsiao, George Marinescu, Huan Wang","doi":"10.1007/s12220-022-00990-4","DOIUrl":"https://doi.org/10.1007/s12220-022-00990-4","url":null,"abstract":"<p><p>We prove a Bochner-Kodaira-Nakano formula and establish Szegő kernel expansions on complete strictly pseudoconvex CR manifolds with transversal CR <math><mi>R</mi></math> -action under certain natural geometric conditions. As a consequence we show that such manifolds are locally CR embeddable.</p>","PeriodicalId":56121,"journal":{"name":"Journal of Geometric Analysis","volume":"32 11","pages":"266"},"PeriodicalIF":1.1,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9387902/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"40437983","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":"Analytic Torsion of Generic Rank Two Distributions in Dimension Five.","authors":"Stefan Haller","doi":"10.1007/s12220-022-00987-z","DOIUrl":"10.1007/s12220-022-00987-z","url":null,"abstract":"<p><p>We propose an analytic torsion for the Rumin complex associated with generic rank two distributions on closed 5-manifolds. This torsion behaves as expected with respect to Poincaré duality and finite coverings. We establish anomaly formulas, expressing the dependence on the sub-Riemannian metric and the 2-plane bundle in terms of integrals over local quantities. For certain nilmanifolds, we are able to show that this torsion coincides with the Ray-Singer analytic torsion, up to a constant.</p>","PeriodicalId":56121,"journal":{"name":"Journal of Geometric Analysis","volume":"32 10","pages":"248"},"PeriodicalIF":1.2,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9325871/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"40574965","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":"Hermitian-Yang-Mills Connections on Collapsing Elliptically Fibered <i>K</i>3 Surfaces.","authors":"Ved Datar, Adam Jacob","doi":"10.1007/s12220-021-00808-9","DOIUrl":"https://doi.org/10.1007/s12220-021-00808-9","url":null,"abstract":"<p><p>Let <math><mrow><mi>X</mi> <mo>→</mo> <msup><mrow><mi>P</mi></mrow> <mn>1</mn></msup> </mrow> </math> be an elliptically fibered <i>K</i>3 surface, admitting a sequence <math><msub><mi>ω</mi> <mi>i</mi></msub> </math> of Ricci-flat metrics collapsing the fibers. Let <i>V</i> be a holomorphic <i>SU</i>(<i>n</i>) bundle over <i>X</i>, stable with respect to <math><msub><mi>ω</mi> <mi>i</mi></msub> </math> . Given the corresponding sequence <math><msub><mi>Ξ</mi> <mi>i</mi></msub> </math> of Hermitian-Yang-Mills connections on <i>V</i>, we prove that, if <i>E</i> is a generic fiber, the restricted sequence <math> <mrow><msub><mi>Ξ</mi> <mi>i</mi></msub> <msub><mrow><mo>|</mo></mrow> <mi>E</mi></msub> </mrow> </math> converges to a flat connection <math><msub><mi>A</mi> <mn>0</mn></msub> </math> . Furthermore, if the restriction <math> <msub><mrow><mi>V</mi> <mo>|</mo></mrow> <mi>E</mi></msub> </math> is of the form <math> <mrow><msubsup><mo>⊕</mo> <mrow><mi>j</mi> <mo>=</mo> <mn>1</mn></mrow> <mi>n</mi></msubsup> <msub><mi>O</mi> <mi>E</mi></msub> <mrow><mo>(</mo> <msub><mi>q</mi> <mi>j</mi></msub> <mo>-</mo> <mn>0</mn> <mo>)</mo></mrow> </mrow> </math> for <i>n</i> distinct points <math> <mrow><msub><mi>q</mi> <mi>j</mi></msub> <mo>∈</mo> <mi>E</mi></mrow> </math> , then these points uniquely determine <math><msub><mi>A</mi> <mn>0</mn></msub> </math> .</p>","PeriodicalId":56121,"journal":{"name":"Journal of Geometric Analysis","volume":"32 2","pages":"69"},"PeriodicalIF":1.1,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8741718/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"39882092","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":"On Rectifiable Measures in Carnot Groups: Existence of Density.","authors":"Gioacchino Antonelli, Andrea Merlo","doi":"10.1007/s12220-022-00971-7","DOIUrl":"https://doi.org/10.1007/s12220-022-00971-7","url":null,"abstract":"<p><p>In this paper, we start a detailed study of a new notion of rectifiability in Carnot groups: we say that a Radon measure is <math><msub><mi>P</mi> <mi>h</mi></msub> </math> -rectifiable, for <math><mrow><mi>h</mi> <mo>∈</mo> <mi>N</mi></mrow> </math> , if it has positive <i>h</i>-lower density and finite <i>h</i>-upper density almost everywhere, and, at almost every point, it admits a unique tangent measure up to multiples. First, we compare <math><msub><mi>P</mi> <mi>h</mi></msub> </math> -rectifiability with other notions of rectifiability previously known in the literature in the setting of Carnot groups, and we prove that it is strictly weaker than them. Second, we prove several structure properties of <math><msub><mi>P</mi> <mi>h</mi></msub> </math> -rectifiable measures. Namely, we prove that the support of a <math><msub><mi>P</mi> <mi>h</mi></msub> </math> -rectifiable measure is almost everywhere covered by sets satisfying a cone-like property, and in the particular case of <math><msub><mi>P</mi> <mi>h</mi></msub> </math> -rectifiable measures with complemented tangents, we show that they are supported on the union of intrinsically Lipschitz and differentiable graphs. Such a covering property is used to prove the main result of this paper: we show that a <math><msub><mi>P</mi> <mi>h</mi></msub> </math> -rectifiable measure has almost everywhere positive and finite <i>h</i>-density whenever the tangents admit at least one complementary subgroup.</p>","PeriodicalId":56121,"journal":{"name":"Journal of Geometric Analysis","volume":"32 9","pages":"239"},"PeriodicalIF":1.1,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9293879/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"40534631","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":"Exception Sets of Intrinsic and Piecewise Lipschitz Functions.","authors":"Gunther Leobacher, Alexander Steinicke","doi":"10.1007/s12220-021-00860-5","DOIUrl":"10.1007/s12220-021-00860-5","url":null,"abstract":"<p><p>We consider a class of functions defined on metric spaces which generalizes the concept of piecewise Lipschitz continuous functions on an interval or on polyhedral structures. The study of such functions requires the investigation of their exception sets where the Lipschitz property fails. The newly introduced notion of permeability describes sets which are natural exceptions for Lipschitz continuity in a well-defined sense. One of the main results states that continuous functions which are intrinsically Lipschitz continuous outside a permeable set are Lipschitz continuous on the whole domain with respect to the intrinsic metric. We provide examples of permeable sets in <math> <msup><mrow><mi>R</mi></mrow> <mi>d</mi></msup> </math> , which include Lipschitz submanifolds.</p>","PeriodicalId":56121,"journal":{"name":"Journal of Geometric Analysis","volume":"32 4","pages":"118"},"PeriodicalIF":1.1,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8807473/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"39914097","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":"Bakry-Émery Ricci Curvature Bounds for Doubly Warped Products of Weighted Spaces.","authors":"Zohreh Fathi, Sajjad Lakzian","doi":"10.1007/s12220-021-00745-7","DOIUrl":"https://doi.org/10.1007/s12220-021-00745-7","url":null,"abstract":"<p><p>We introduce a notion of doubly warped product of weighted graphs that is consistent with the doubly warped product in the Riemannian setting. We establish various discrete Bakry-Émery Ricci curvature-dimension bounds for such warped products in terms of the curvature of the constituent graphs. This requires deliberate analysis of the quadratic forms involved, prompting the introduction of some crucial notions such as curvature saturation at a vertex. In the spirit of being thorough and to provide a frame of reference, we also introduce the <math> <mfenced><msub><mi>R</mi> <mn>1</mn></msub> <mo>,</mo> <msub><mi>R</mi> <mn>2</mn></msub> </mfenced> </math> -doubly warped products of smooth measure spaces and establish <math><mi>N</mi></math> -Bakry-Émery Ricci curvature (lower) bounds thereof in terms of those of the factors. At the end of these notes, we present examples and demonstrate applications of warped products with some toy models.</p>","PeriodicalId":56121,"journal":{"name":"Journal of Geometric Analysis","volume":"32 3","pages":"79"},"PeriodicalIF":1.1,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8753965/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"39687129","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":"The Fundamental Solution to $$Box _b$$ on Quadric Manifolds: Part 3. Asymptotics for a Codimension 2 Case in $${mathbb {C}}^4$$","authors":"A. Boggess, A. Raich","doi":"10.1007/S12220-021-00693-2","DOIUrl":"https://doi.org/10.1007/S12220-021-00693-2","url":null,"abstract":"","PeriodicalId":56121,"journal":{"name":"Journal of Geometric Analysis","volume":"1 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2021-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1007/S12220-021-00693-2","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42658630","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":"Discrete Subgroups of $$text{ PSL }(n+1,{mathbb {C}})$$ Acting on the Grassmannians","authors":"Haremy Zúñiga","doi":"10.1007/S12220-021-00651-Y","DOIUrl":"https://doi.org/10.1007/S12220-021-00651-Y","url":null,"abstract":"","PeriodicalId":56121,"journal":{"name":"Journal of Geometric Analysis","volume":"1 1","pages":"1-28"},"PeriodicalIF":1.1,"publicationDate":"2021-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1007/S12220-021-00651-Y","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49335966","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}