Marcos M. Alexandrino, Leonardo F. Cavenaghi, Diego Corro, Marcelo K. Inagaki
{"title":"Singular Riemannian foliations, variational problems and principles of symmetric criticalities","authors":"Marcos M. Alexandrino, Leonardo F. Cavenaghi, Diego Corro, Marcelo K. Inagaki","doi":"10.1007/s10231-026-01679-z","DOIUrl":"10.1007/s10231-026-01679-z","url":null,"abstract":"<div><p>A singular foliation <span>(mathscr {F})</span> on a complete Riemannian manifold <i>M</i> is called a Singular Riemannian foliation (SRF for short) if its leaves are locally equidistant, e.g., the partition of <i>M</i> into the orbits of a Lie group action by isometries. In this paper, we investigate variational problems in compact Riemannian manifolds equipped with SRFs with special properties, which we name as AVP. Examples of such SRFs being considered include isoparametric foliations, SRFs on Euclidean fiber bundles, and the partition of <i>M</i> into the orbits of a Lie group acting by isometries. More precisely, we prove an analog to Palais’ Principle of Symmetric Criticality for <span>(mathscr {F})</span>-symmetric integral operators on the Banach spaces <span>(W^{1,p}(M).)</span> This result together with a version of the Rellich–Kondrachov–Hebey–Vaugon Embedding Theorem for <span>(mathscr {F})</span>-basic Sobolev functions allows us to circumvent difficulties with Sobolev’s critical exponents when considering applications of techniques from Calculus of Variations to find solutions to PDEs. To exemplify this, we prove the existence of countably infinite many weak solutions to a class of variational problems, which includes <i>p</i>-Kirchhoff problems for manifolds equipped with an AVP foliation.</p></div>","PeriodicalId":8265,"journal":{"name":"Annali di Matematica Pura ed Applicata","volume":"205 5","pages":"2507 - 2572"},"PeriodicalIF":0.9,"publicationDate":"2026-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10231-026-01679-z.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149176894","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Albetã C. Mafra, Carlos Peñafiel, Erick J. Palacios Escobar
{"title":"Elliptic Weingarten surfaces of minimal type invariant by left translations in (textrm{Sol}_3)","authors":"Albetã C. Mafra, Carlos Peñafiel, Erick J. Palacios Escobar","doi":"10.1007/s10231-026-01674-4","DOIUrl":"10.1007/s10231-026-01674-4","url":null,"abstract":"<div><p>In this article, we show the existence and uniqueness of a family of complete elliptic Weingarten surfaces of minimal type, which are invariant by a uniparametric group of horizontal translation. Moreover, we give a complete description of the generating curve of each of these surfaces when the elliptic function satisfies <span>(f(x)>0)</span> for <span>(xne 0)</span>.</p></div>","PeriodicalId":8265,"journal":{"name":"Annali di Matematica Pura ed Applicata","volume":"205 5","pages":"2369 - 2388"},"PeriodicalIF":0.9,"publicationDate":"2026-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149176594","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Total (mathbb {A})-variation flows","authors":"David Meyer","doi":"10.1007/s10231-026-01688-y","DOIUrl":"10.1007/s10231-026-01688-y","url":null,"abstract":"<div><p>We study the <span>(L^2)</span>-gradient flows, <span>(partial _t u-operatorname {div}(textrm{D}f(x,mathbb {A}u))=0)</span>, of functionals of the type <span>(int _{Omega }f(x,mathbb {A}u),textrm{d}x)</span>, where <i>f</i> is a convex function of linear growth and <span>(mathbb {A})</span> is some first-order linear constant-coefficient differential operator. To this end, we identify the relaxation of the functional to the space <span>(BV^mathbb {A}cap L^2)</span>, identify its subdifferential, and show pointwise representation formulas for the relaxation and the subdifferential, both with and without Dirichlet boundary conditions. The existence and uniqueness then follow from abstract semigroup theory. We further show that our solutions can be obtained as limits of the corresponding flows with <i>p</i>-growth as <span>(psearrow 1)</span>.</p></div>","PeriodicalId":8265,"journal":{"name":"Annali di Matematica Pura ed Applicata","volume":"205 5","pages":"2819 - 2856"},"PeriodicalIF":0.9,"publicationDate":"2026-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10231-026-01688-y.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149176609","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Reduction principles for proper actions","authors":"Leonardo Biliotti, Gustavo May-Custodio, Alessandro Minuzzo","doi":"10.1007/s10231-026-01687-z","DOIUrl":"10.1007/s10231-026-01687-z","url":null,"abstract":"<div>\u0000 \u0000 <p>We study the <i>core</i> of a proper action by a Lie group <i>G</i> on a smooth manifold <i>M</i>, extending the construction for <i>G</i> compact by Skjelbred and Straume (A note on the reduction principle for compact transformation groups, 1995). Moreover, we show that many properties of a proper <i>G</i>-action on <i>M</i> are determined by the action of a group <span>(G')</span> on the corresponding core <span>( _cM)</span>. We say that such properties admit a <i>reduction principle</i>. In particular, we prove that a proper isometric <i>G</i>-action on <i>M</i> is polar (resp. hyperpolar) if and only if the <span>(G')</span>-action on <span>( _cM)</span> is polar (resp. hyperpolar). In the case of a proper action by symplectomorphisms on a symplectic manifold, we show that a reduction principle holds for coisotropic and infinitesimally almost homogeneous actions. We further study the coisotropic condition for the case of a proper Hamiltonian action and its relation with the symplectic stratification described by Lermann and Bates (Pac J Math 181:201–229, 1997). In particular, we obtain several characterizations for coisotropic actions, some of which extend known results for the action of a compact group of holomorphic automorphisms on a compact Kähler manifold obtained by Huckleberry and Wurzbacher (Math Ann 286:261–280, 1990). Finally, we study some applications of the core construction for the action of a compact Lie group on a Kähler manifold by holomorphic isometries.</p>\u0000 </div>","PeriodicalId":8265,"journal":{"name":"Annali di Matematica Pura ed Applicata","volume":"205 5","pages":"2777 - 2817"},"PeriodicalIF":0.9,"publicationDate":"2026-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10231-026-01687-z.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149176531","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Groups of order 64 and non-homeomorphic double Kodaira fibrations with the same biregular invariants","authors":"Francesco Polizzi, Pietro Sabatino","doi":"10.1007/s10231-026-01691-3","DOIUrl":"10.1007/s10231-026-01691-3","url":null,"abstract":"<div>\u0000 \u0000 <p>Let <span>(Sigma _b)</span> be a compact Riemann surface of genus <i>b</i>. We investigate finite quotients <i>G</i> of the pure braid group on two strands <span>(textsf{P}_2(Sigma _b))</span> which do not factor through <span>(pi _1(Sigma _b times Sigma _b))</span>. Building on our previous work on some special systems of generators on finite groups that we called <i>diagonal double Kodaira structures</i>, we prove that, if <i>G</i> does not have order 32, then <span>(|G| ge 64)</span>, and we completely classify the cases where <span>(b=2)</span> and equality holds. In the last section, as a geometric application of our algebraic results, we construct two 3-dimensional families of double Kodaira fibrations having the same biregular invariants and the same Betti numbers but different fundamental group.</p>\u0000 </div>","PeriodicalId":8265,"journal":{"name":"Annali di Matematica Pura ed Applicata","volume":"205 5","pages":"2897 - 2922"},"PeriodicalIF":0.9,"publicationDate":"2026-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10231-026-01691-3.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149176504","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Energy asymptotics and blow-up phenomena for biharmonic Brézis-Nirenberg problem","authors":"Jiamo Li, Qikai Lu, Minbo Yang","doi":"10.1007/s10231-026-01684-2","DOIUrl":"10.1007/s10231-026-01684-2","url":null,"abstract":"<div>\u0000 \u0000 <p>For dimensions <span>(nge 8)</span>, we are concerned with the quotient functional of the biharmonic Brézis-Nirenberg problem under the Navier boundary condition </p><div><div><span>$$ S(varepsilon V):=inf _{0not equiv uin H^2(Omega )cap H_0^1(Omega )}frac{int _{Omega }|Delta u|^2dx+varepsilon int _{Omega }V|u|^2dx}{big (int _{Omega }|u|^{2^star }dxbig )^{2/2^star }}, $$</span></div></div><p>where <span>(2^star =frac{2n}{n-4})</span> is the critical Sobolev exponent of the embedding <span>(H^2(Omega )cap H_0^1(Omega )hookrightarrow L^{2^star }(Omega ))</span>, <span>(Omega subset mathbb {R}^n)</span> is a bounded open set and <span>(V:overline{Omega }rightarrow mathbb {R})</span> is a continuous function. Under certain assumptions on <i>V</i>, we establish sharp asymptotics for the energy difference <span>(S(0)-S(varepsilon V))</span>, as <span>(varepsilon rightarrow 0^+)</span>, by means of matching upper and lower bound estimates. Moreover, we give a precise description of the blow-up profile of (almost) minimizing sequences and characterize the blow-up rate and the location of concentration points.</p>\u0000 </div>","PeriodicalId":8265,"journal":{"name":"Annali di Matematica Pura ed Applicata","volume":"205 5","pages":"2679 - 2704"},"PeriodicalIF":0.9,"publicationDate":"2026-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149176495","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A uniqueness result in the inverse problem for the anisotropic Schrödinger type equation from local measurements","authors":"Niall Donlon, Romina Gaburro","doi":"10.1007/s10231-026-01686-0","DOIUrl":"10.1007/s10231-026-01686-0","url":null,"abstract":"<div><p>We consider the inverse boundary value problem of the simultaneous determination of the coefficients <span>(sigma )</span> and <i>q</i> of the equation <span>(-text{ div }(sigma nabla u)+qu = 0)</span> from knowledge of the so-called Neumann-to-Dirichlet map, given locally on a non-empty curved portion <span>(Sigma )</span> of the boundary <span>(partial Omega )</span> of a domain <span>(Omega subset mathbb {R}^n)</span>, with <span>(nge 3)</span>. We assume that <span>(sigma )</span> and <i>q</i> are a-priori known to be a piecewise constant matrix-valued and scalar function, respectively, on a given partition of <span>(Omega )</span> with curved interfaces. We prove that <span>(sigma )</span> and <i>q</i> can be uniquely determined in <span>(Omega )</span> from the knowledge of the local map.</p></div>","PeriodicalId":8265,"journal":{"name":"Annali di Matematica Pura ed Applicata","volume":"205 5","pages":"2747 - 2775"},"PeriodicalIF":0.9,"publicationDate":"2026-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10231-026-01686-0.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149176498","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Remark on Laplacians and Riemannian submersions with totally geodesic fibers","authors":"Kazumasa Narita","doi":"10.1007/s10231-026-01682-4","DOIUrl":"10.1007/s10231-026-01682-4","url":null,"abstract":"<div>\u0000 \u0000 <p>Given a Riemannian submersion <span>((M,g) rightarrow (B,j))</span> each of whose fibers is connected and totally geodesic, we consider a certain 1-parameter family of Riemannian metrics <span>((g_{t})_{t > 0})</span> on <i>M</i>, which is called the canonical variation. Let <span>(lambda _{1}(g_{t}))</span> be the first positive eigenvalue of the Laplace–Beltrami operator <span>(Delta ^{M}_{g_{t}})</span> and <span>(hbox {Vol}(M,g_{t}))</span> the volume of <span>((M, g_{t}))</span>. In Bérard-Bergery and Bourguignon (Ill J Math 26(2):181–200,1982 ) showed that the scale-invariant quantity <span>(lambda _{1}(g_{t})hbox {Vol}(M,g_{t})^{2/hbox {dim}M})</span> goes to 0 with <i>t</i>. In this paper, we show that if each fiber is Einstein and (<i>M</i>, <i>g</i>) satisfies a certain condition about its Ricci curvature, then bounds for <span>(lambda _{1}(g_{t}))</span> can be obtained. In particular this implies that <span>(lambda _{1}(g_{t})hbox {Vol}(M,g_{t})^{2/hbox {dim}M})</span> goes to <span>(infty )</span> with <i>t</i>. Moreover, using these bounds, we consider stability of <span>(g_{t})</span> as a critical point of the Yamabe functional.</p>\u0000 </div>","PeriodicalId":8265,"journal":{"name":"Annali di Matematica Pura ed Applicata","volume":"205 5","pages":"2629 - 2650"},"PeriodicalIF":0.9,"publicationDate":"2026-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149176497","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"On the blow up of (C^1) solutions of the isentropic Euler system","authors":"Shyam Sundar Ghoshal, Animesh Jana","doi":"10.1007/s10231-026-01680-6","DOIUrl":"10.1007/s10231-026-01680-6","url":null,"abstract":"<div><p>In this article, we study the break-down of smooth and continuous solutions to isentropic Euler system in multi dimension. Sideris (Comm Math Phys 101(4):475–478, 1985) proved the blow up of smooth solutions when initial data satisfies an ‘integral condition’. We show that a <span>(C^1)</span> solution of isentropic Euler equation breaks down if (i) gradient of initial velocity has a negative real eigenvalue at some point <span>(x_0in mathbb {R}^d)</span> and (ii) Hessian of initial density satisfies a smallness condition in Sobolev space. Our proof also works for the data which fails to satisfy the above-mentioned ‘integral condition’. Furthermore, we prove the global existence of smooth solution when (i) eigenvalues of gradient of initial velocity have non-negative real-part and (ii) initial density satisfies a smallness condition. This extends the global existence result of Grassin (Indiana Univ Math J 47(4):1397–1432, 1998). Another goal of this article is to study the breakdown of continuous weak solutions of isentropic Euler equations. We are able to show that the ‘integral condition’ of Sideris can cause the breakdown of continuous solutions in finite time. This improves the blow up result of Sideris from <span>(C^1)</span> to continuous space.</p></div>","PeriodicalId":8265,"journal":{"name":"Annali di Matematica Pura ed Applicata","volume":"205 5","pages":"2573 - 2609"},"PeriodicalIF":0.9,"publicationDate":"2026-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149176564","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Marianna Chatzakou, Aidyn Kassymov, Michael Ruzhansky
{"title":"Fujita exponent for heat equation with Hörmander vector fields","authors":"Marianna Chatzakou, Aidyn Kassymov, Michael Ruzhansky","doi":"10.1007/s10231-026-01683-3","DOIUrl":"10.1007/s10231-026-01683-3","url":null,"abstract":"<div>\u0000 \u0000 <p>In this paper, we show global existence and non-existence results for the heat equation with sum of the squares of smooth vector fields on <span>(mathbb {R}^{n})</span> satisfying Hörmander’s rank condition with a non-linearity of the form <i>f</i>(<i>u</i>), where <i>f</i> is a suitable function and <i>u</i> is the solution. In particular, when <span>(f(u)=u^p)</span>, we calculate the critical Fujita exponent. We also give necessary conditions for blow-up or, alternatively, a sufficient condition for the existence of positive global solutions for time-dependent nonlinearities of the type <span>(varphi (t)f(u))</span>.</p>\u0000 </div>","PeriodicalId":8265,"journal":{"name":"Annali di Matematica Pura ed Applicata","volume":"205 5","pages":"2651 - 2678"},"PeriodicalIF":0.9,"publicationDate":"2026-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10231-026-01683-3.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149176494","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}