Pub Date : 2025-09-11DOI: 10.1016/j.difgeo.2025.102290
Ali Suri
This paper explores the application of central extensions of Lie groups and Lie algebras to derive the viscous quasi-geostrophic (QGS) equations, with and without Rayleigh friction term, on the torus as critical points of a stochastic Lagrangian. We begin by introducing central extensions and proving the integrability of the Roger Lie algebra cocycle , which is used to model the QGS on the torus. Incorporating stochastic perturbations, we formulate two specific semi-martingales on the central extension and study the stochastic Euler-Poincaré reduction. Specifically, we add stochastic perturbations to the part of the extended Lie algebra and prove that the resulting critical points of the stochastic right-invariant Lagrangian solve the viscous QGS equation, with and without Rayleigh friction term.
{"title":"Stochastic Euler-Poincaré reduction for central extension","authors":"Ali Suri","doi":"10.1016/j.difgeo.2025.102290","DOIUrl":"10.1016/j.difgeo.2025.102290","url":null,"abstract":"<div><div>This paper explores the application of central extensions of Lie groups and Lie algebras to derive the viscous quasi-geostrophic (QGS) equations, with and without Rayleigh friction term, on the torus as critical points of a stochastic Lagrangian. We begin by introducing central extensions and proving the integrability of the Roger Lie algebra cocycle <span><math><msub><mrow><mi>ω</mi></mrow><mrow><mi>α</mi></mrow></msub></math></span>, which is used to model the QGS on the torus. Incorporating stochastic perturbations, we formulate two specific semi-martingales on the central extension and study the stochastic Euler-Poincaré reduction. Specifically, we add stochastic perturbations to the <span><math><mi>g</mi></math></span> part of the extended Lie algebra <span><math><mover><mrow><mi>g</mi></mrow><mrow><mo>ˆ</mo></mrow></mover><mo>=</mo><mi>g</mi><msub><mrow><mo>⋊</mo></mrow><mrow><msub><mrow><mi>ω</mi></mrow><mrow><mi>α</mi></mrow></msub></mrow></msub><mi>R</mi></math></span> and prove that the resulting critical points of the stochastic right-invariant Lagrangian solve the viscous QGS equation, with and without Rayleigh friction term.</div></div>","PeriodicalId":51010,"journal":{"name":"Differential Geometry and its Applications","volume":"101 ","pages":"Article 102290"},"PeriodicalIF":0.7,"publicationDate":"2025-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145049116","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-11DOI: 10.1016/j.difgeo.2025.102289
Gherici Beldjilali
In this paper, we obtain some necessary and sufficient conditions for a vector field on a 3-dimensional -manifold to be minimal or harmonic. We construct some examples to illustrate main results.
本文给出了三维c12流形上向量场最小或调和的几个充要条件。我们构造了一些例子来说明主要结果。
{"title":"Minimal and harmonic vector fields on three-dimensional C12-manifolds","authors":"Gherici Beldjilali","doi":"10.1016/j.difgeo.2025.102289","DOIUrl":"10.1016/j.difgeo.2025.102289","url":null,"abstract":"<div><div>In this paper, we obtain some necessary and sufficient conditions for a vector field on a 3-dimensional <span><math><msub><mrow><mi>C</mi></mrow><mrow><mn>12</mn></mrow></msub></math></span>-manifold to be minimal or harmonic. We construct some examples to illustrate main results.</div></div>","PeriodicalId":51010,"journal":{"name":"Differential Geometry and its Applications","volume":"101 ","pages":"Article 102289"},"PeriodicalIF":0.7,"publicationDate":"2025-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145049117","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-09DOI: 10.1016/j.difgeo.2025.102288
Salah Chaib , Ana Cristina Ferreira , Abdelghani Zeghib
Let us call pseudo-homothetic group the non-unimodular 3-dimensional Lie group that is the semi-direct product of acting non-semisimply on . In this article, we solve the geodesic completeness problem on this Lie group. In particular, we exhibit a family of complete metrics such that all geodesics have bounded velocity. As an application, we show that the set of complete metrics is not closed.
{"title":"The completeness problem on the pseudo-homothetic Lie group","authors":"Salah Chaib , Ana Cristina Ferreira , Abdelghani Zeghib","doi":"10.1016/j.difgeo.2025.102288","DOIUrl":"10.1016/j.difgeo.2025.102288","url":null,"abstract":"<div><div>Let us call pseudo-homothetic group the non-unimodular 3-dimensional Lie group that is the semi-direct product of <span><math><mi>R</mi></math></span> acting non-semisimply on <span><math><msup><mrow><mi>R</mi></mrow><mrow><mn>2</mn></mrow></msup></math></span>. In this article, we solve the geodesic completeness problem on this Lie group. In particular, we exhibit a family of complete metrics such that all geodesics have bounded velocity. As an application, we show that the set of complete metrics is not closed.</div></div>","PeriodicalId":51010,"journal":{"name":"Differential Geometry and its Applications","volume":"101 ","pages":"Article 102288"},"PeriodicalIF":0.7,"publicationDate":"2025-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145020440","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-09DOI: 10.1016/j.difgeo.2025.102279
Qing Cui
We show that a closed minimal hypersurface in with constant scalar curvature and zero Gauss curvature is totally geodesic, which gives a support to strong version of Chern conjecture.
{"title":"Minimal hypersurfaces in S5 with constant scalar curvature and zero Gauss curvature","authors":"Qing Cui","doi":"10.1016/j.difgeo.2025.102279","DOIUrl":"10.1016/j.difgeo.2025.102279","url":null,"abstract":"<div><div>We show that a closed minimal hypersurface in <span><math><msup><mrow><mi>S</mi></mrow><mrow><mn>5</mn></mrow></msup></math></span> with constant scalar curvature and zero Gauss curvature is totally geodesic, which gives a support to strong version of Chern conjecture.</div></div>","PeriodicalId":51010,"journal":{"name":"Differential Geometry and its Applications","volume":"101 ","pages":"Article 102279"},"PeriodicalIF":0.7,"publicationDate":"2025-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145020439","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-02DOI: 10.1016/j.difgeo.2025.102278
Jun Jiang, Yunhe Sheng, Geyi Sun
In this paper, first we use the higher derived brackets to construct an -algebra, whose Maurer-Cartan elements are 3-Lie algebra morphisms. Using the differential in the -algebra that govern deformations of the morphism, we give the cohomology of a 3-Lie algebra morphism. Then we study the rigidity and stability of 3-Lie algebra morphisms using the established cohomology theory. In particular, we show that if the first cohomology group is trivial, then the morphism is rigid; if the second cohomology group is trivial, then the morphism is stable. Finally, we study the stability of 3-Lie subalgebras similarly.
{"title":"Stability and rigidity of 3-Lie algebra morphisms","authors":"Jun Jiang, Yunhe Sheng, Geyi Sun","doi":"10.1016/j.difgeo.2025.102278","DOIUrl":"10.1016/j.difgeo.2025.102278","url":null,"abstract":"<div><div>In this paper, first we use the higher derived brackets to construct an <span><math><msub><mrow><mi>L</mi></mrow><mrow><mo>∞</mo></mrow></msub></math></span>-algebra, whose Maurer-Cartan elements are 3-Lie algebra morphisms. Using the differential in the <span><math><msub><mrow><mi>L</mi></mrow><mrow><mo>∞</mo></mrow></msub></math></span>-algebra that govern deformations of the morphism, we give the cohomology of a 3-Lie algebra morphism. Then we study the rigidity and stability of 3-Lie algebra morphisms using the established cohomology theory. In particular, we show that if the first cohomology group is trivial, then the morphism is rigid; if the second cohomology group is trivial, then the morphism is stable. Finally, we study the stability of 3-Lie subalgebras similarly.</div></div>","PeriodicalId":51010,"journal":{"name":"Differential Geometry and its Applications","volume":"101 ","pages":"Article 102278"},"PeriodicalIF":0.7,"publicationDate":"2025-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144933732","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-08-25DOI: 10.1016/j.difgeo.2025.102277
Noriaki Ikeda
We propose a Hamiltonian Lie algebroid and a momentum section over a Dirac structure as a generalization of a Hamiltonian Lie algebroid over a pre-symplectic manifold and one over a Poisson manifold. A Hamiltonian Lie algebroid and a momentum section generalize a Hamiltonian G-space and a momentum map over a symplectic manifold. We prove some properties of this new Hamiltonian Lie algebroid and construct a mechanics based on this structure as an application. These new mechanics are called the gauged Poisson sigma model and the gauged Dirac sigma model.
{"title":"Hamilton Lie algebroids over Dirac structures and sigma models","authors":"Noriaki Ikeda","doi":"10.1016/j.difgeo.2025.102277","DOIUrl":"10.1016/j.difgeo.2025.102277","url":null,"abstract":"<div><div>We propose a Hamiltonian Lie algebroid and a momentum section over a Dirac structure as a generalization of a Hamiltonian Lie algebroid over a pre-symplectic manifold and one over a Poisson manifold. A Hamiltonian Lie algebroid and a momentum section generalize a Hamiltonian <em>G</em>-space and a momentum map over a symplectic manifold. We prove some properties of this new Hamiltonian Lie algebroid and construct a mechanics based on this structure as an application. These new mechanics are called the gauged Poisson sigma model and the gauged Dirac sigma model.</div></div>","PeriodicalId":51010,"journal":{"name":"Differential Geometry and its Applications","volume":"100 ","pages":"Article 102277"},"PeriodicalIF":0.7,"publicationDate":"2025-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144893640","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-08-25DOI: 10.1016/j.difgeo.2025.102276
Guido Carlet , Matteo Casati
We consider an arbitrary Dubrovin-Novikov bracket of degree k, namely a homogeneous degree k local Poisson bracket on the loop space of a smooth manifold M of dimension n, and show that k connections, defined by explicit linear combinations with constant coefficients of the standard connections associated with the Poisson bracket, are flat.
{"title":"On the structure of homogeneous local Poisson brackets","authors":"Guido Carlet , Matteo Casati","doi":"10.1016/j.difgeo.2025.102276","DOIUrl":"10.1016/j.difgeo.2025.102276","url":null,"abstract":"<div><div>We consider an arbitrary Dubrovin-Novikov bracket of degree <em>k</em>, namely a homogeneous degree <em>k</em> local Poisson bracket on the loop space of a smooth manifold <em>M</em> of dimension <em>n</em>, and show that <em>k</em> connections, defined by explicit linear combinations with constant coefficients of the standard connections associated with the Poisson bracket, are flat.</div></div>","PeriodicalId":51010,"journal":{"name":"Differential Geometry and its Applications","volume":"100 ","pages":"Article 102276"},"PeriodicalIF":0.7,"publicationDate":"2025-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144893641","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-08-20DOI: 10.1016/j.difgeo.2025.102275
Kurando Baba , Kazuto Shintani
F-Yang-Mills connections are critical points of F-Yang Mills functional on the space of connections of a principal fiber bundle, which are generalizations of Yang-Mills connections, p-Yang-Mills connections and exponential Yang-Mills connections and so on. Here, F is a strictly increasing -function. In this paper, we extend Simons theorem for the instability of Yang-Mills connections to F-Yang-Mills connections. We derive a sufficient condition that any non-flat, F-Yang-Mills connection over submanifolds in a Euclidean space is unstable. In the standard sphere case, this condition is expressed by an inequality involving its dimension and the degree of the differential of the function F. Our main results are proved by extending Kobayashi-Ohnita-Takeuchi's calculation to F-Yang-Mills connections.
{"title":"A Simons type condition for instability of F-Yang-Mills connections","authors":"Kurando Baba , Kazuto Shintani","doi":"10.1016/j.difgeo.2025.102275","DOIUrl":"10.1016/j.difgeo.2025.102275","url":null,"abstract":"<div><div><em>F</em>-Yang-Mills connections are critical points of <em>F</em>-Yang Mills functional on the space of connections of a principal fiber bundle, which are generalizations of Yang-Mills connections, <em>p</em>-Yang-Mills connections and exponential Yang-Mills connections and so on. Here, <em>F</em> is a strictly increasing <span><math><msup><mrow><mi>C</mi></mrow><mrow><mn>2</mn></mrow></msup></math></span>-function. In this paper, we extend Simons theorem for the instability of Yang-Mills connections to <em>F</em>-Yang-Mills connections. We derive a sufficient condition that any non-flat, <em>F</em>-Yang-Mills connection over submanifolds in a Euclidean space is unstable. In the standard sphere case, this condition is expressed by an inequality involving its dimension and the degree of the differential of the function <em>F</em>. Our main results are proved by extending Kobayashi-Ohnita-Takeuchi's calculation to <em>F</em>-Yang-Mills connections.</div></div>","PeriodicalId":51010,"journal":{"name":"Differential Geometry and its Applications","volume":"100 ","pages":"Article 102275"},"PeriodicalIF":0.7,"publicationDate":"2025-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144867305","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-08-01DOI: 10.1016/j.difgeo.2025.102273
Ana Carolina Mançur
We extend the characterization of Lie bialgebroids via Manin triples to the context of double structures over Lie groupoids. We consider Lie bialgebroid groupoids, given by LA-groupoids in duality, and establish their correspondence with multiplicative Manin triples, i.e., CA-groupoids equipped with a pair of complementary multiplicative Dirac structures. As an application, we give a new viewpoint to the co-quadratic Lie algebroids of Lang, Qiao, and Yin [13] and the Manin triple description of Lie bialgebroid crossed modules.
{"title":"Manin triples on multiplicative Courant algebroids","authors":"Ana Carolina Mançur","doi":"10.1016/j.difgeo.2025.102273","DOIUrl":"10.1016/j.difgeo.2025.102273","url":null,"abstract":"<div><div>We extend the characterization of Lie bialgebroids via Manin triples to the context of double structures over Lie groupoids. We consider Lie bialgebroid groupoids, given by LA-groupoids in duality, and establish their correspondence with multiplicative Manin triples, i.e., CA-groupoids equipped with a pair of complementary multiplicative Dirac structures. As an application, we give a new viewpoint to the co-quadratic Lie algebroids of Lang, Qiao, and Yin <span><span>[13]</span></span> and the Manin triple description of Lie bialgebroid crossed modules.</div></div>","PeriodicalId":51010,"journal":{"name":"Differential Geometry and its Applications","volume":"100 ","pages":"Article 102273"},"PeriodicalIF":0.7,"publicationDate":"2025-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144757592","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-07-16DOI: 10.1016/j.difgeo.2025.102272
Antonio Michele Miti , Leonid Ryvkin
The purpose of this paper is to present a fully algebraic formalism for the construction and reduction of -algebras of observables inspired by multisymplectic geometry, using Gerstenhaber algebras, BV-modules, and the constraint triple formalism. In the “geometric case”, we reconstruct and conceptually explain the recent results of [7].
{"title":"Multisymplectic observable reduction using constraint triples","authors":"Antonio Michele Miti , Leonid Ryvkin","doi":"10.1016/j.difgeo.2025.102272","DOIUrl":"10.1016/j.difgeo.2025.102272","url":null,"abstract":"<div><div>The purpose of this paper is to present a fully algebraic formalism for the construction and reduction of <span><math><msub><mrow><mi>L</mi></mrow><mrow><mo>∞</mo></mrow></msub></math></span>-algebras of observables inspired by multisymplectic geometry, using Gerstenhaber algebras, BV-modules, and the constraint triple formalism. In the “geometric case”, we reconstruct and conceptually explain the recent results of <span><span>[7]</span></span>.</div></div>","PeriodicalId":51010,"journal":{"name":"Differential Geometry and its Applications","volume":"100 ","pages":"Article 102272"},"PeriodicalIF":0.6,"publicationDate":"2025-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144634476","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}