Pub Date : 2024-04-17DOI: 10.1016/j.difgeo.2024.102137
Guangzu Chen , Jiayu Liao, Lihong Liu
In this paper, we find a new tensor which is responsible for Finsler metrics with reversible geodesics. Using this tensor, we can prove that Finsler metrics are Douglas metrics if and only if they have reversible geodesics and Douglas curvature. Further, we focus on Finsler metrics with reversible Douglas curvature.
{"title":"On Finsler metrics with reversible Douglas curvature","authors":"Guangzu Chen , Jiayu Liao, Lihong Liu","doi":"10.1016/j.difgeo.2024.102137","DOIUrl":"https://doi.org/10.1016/j.difgeo.2024.102137","url":null,"abstract":"<div><p>In this paper, we find a new tensor which is responsible for Finsler metrics with reversible geodesics. Using this tensor, we can prove that Finsler metrics are Douglas metrics if and only if they have reversible geodesics and Douglas curvature. Further, we focus on Finsler metrics with reversible Douglas curvature.</p></div>","PeriodicalId":51010,"journal":{"name":"Differential Geometry and its Applications","volume":"94 ","pages":"Article 102137"},"PeriodicalIF":0.5,"publicationDate":"2024-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140557439","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 : 2024-04-02DOI: 10.1016/j.difgeo.2024.102135
Andrés Ahumada Gómez , Mauricio Che
We study the Gromov–Hausdorff convergence of metric pairs and metric tuples and prove the equivalence of different natural definitions of this concept. We also prove embedding, completeness and compactness theorems in this setting. Finally, we get a relative version of Fukaya's theorem about quotient spaces under Gromov–Hausdorff equivariant convergence and a version of Grove–Petersen–Wu's finiteness theorem for stratified spaces.
{"title":"Gromov–Hausdorff convergence of metric pairs and metric tuples","authors":"Andrés Ahumada Gómez , Mauricio Che","doi":"10.1016/j.difgeo.2024.102135","DOIUrl":"https://doi.org/10.1016/j.difgeo.2024.102135","url":null,"abstract":"<div><p>We study the Gromov–Hausdorff convergence of metric pairs and metric tuples and prove the equivalence of different natural definitions of this concept. We also prove embedding, completeness and compactness theorems in this setting. Finally, we get a relative version of Fukaya's theorem about quotient spaces under Gromov–Hausdorff equivariant convergence and a version of Grove–Petersen–Wu's finiteness theorem for stratified spaces.</p></div>","PeriodicalId":51010,"journal":{"name":"Differential Geometry and its Applications","volume":"94 ","pages":"Article 102135"},"PeriodicalIF":0.5,"publicationDate":"2024-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0926224524000287/pdfft?md5=90e659088fe8f3dd0f018ed3d1606609&pid=1-s2.0-S0926224524000287-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140342326","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-28DOI: 10.1016/j.difgeo.2024.102134
Hugo Cattarucci Botós
We study geometric structures arising from Hermitian forms on linear spaces over real algebras beyond the division ones. Our focus is on the dual numbers, the split-complex numbers, and the split-quaternions. The corresponding geometric structures are employed to describe the spaces of oriented geodesics in the hyperbolic plane, the Euclidean plane, and the round 2-sphere. We also introduce a simple and natural geometric transition between these spaces. Finally, we present a projective model for the hyperbolic bidisc, that is, the Riemannian product of two hyperbolic discs.
{"title":"Geometry over algebras","authors":"Hugo Cattarucci Botós","doi":"10.1016/j.difgeo.2024.102134","DOIUrl":"https://doi.org/10.1016/j.difgeo.2024.102134","url":null,"abstract":"<div><p>We study geometric structures arising from Hermitian forms on linear spaces over real algebras beyond the division ones. Our focus is on the dual numbers, the split-complex numbers, and the split-quaternions. The corresponding geometric structures are employed to describe the spaces of oriented geodesics in the hyperbolic plane, the Euclidean plane, and the round 2-sphere. We also introduce a simple and natural geometric transition between these spaces. Finally, we present a projective model for the hyperbolic bidisc, that is, the Riemannian product of two hyperbolic discs.</p></div>","PeriodicalId":51010,"journal":{"name":"Differential Geometry and its Applications","volume":"94 ","pages":"Article 102134"},"PeriodicalIF":0.5,"publicationDate":"2024-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140320403","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 : 2024-03-27DOI: 10.1016/j.difgeo.2024.102136
Guangyue Huang, Bingqing Ma, Mingfang Zhu
In this paper, we achieve a Reilly type integral formula associated with the ϕ-Laplacian. As its applications, we obtain Heintze-Karcher and Minkowski type inequalities. Furthermore, almost Schur lemmas are also given. They recover the partial results of Li and Xia in [17]. On the other hand, we also study eigenvalue problem for Wentzell boundary conditions and obtain eigenvalue relationships.
{"title":"A Reilly type integral formula and its applications","authors":"Guangyue Huang, Bingqing Ma, Mingfang Zhu","doi":"10.1016/j.difgeo.2024.102136","DOIUrl":"https://doi.org/10.1016/j.difgeo.2024.102136","url":null,"abstract":"<div><p>In this paper, we achieve a Reilly type integral formula associated with the <em>ϕ</em>-Laplacian. As its applications, we obtain Heintze-Karcher and Minkowski type inequalities. Furthermore, almost Schur lemmas are also given. They recover the partial results of Li and Xia in <span>[17]</span>. On the other hand, we also study eigenvalue problem for Wentzell boundary conditions and obtain eigenvalue relationships.</p></div>","PeriodicalId":51010,"journal":{"name":"Differential Geometry and its Applications","volume":"94 ","pages":"Article 102136"},"PeriodicalIF":0.5,"publicationDate":"2024-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140308808","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 : 2024-03-18DOI: 10.1016/j.difgeo.2024.102123
Jean-Philippe Chassé
We study sequences of immersions respecting bounds coming from Riemannian geometry and apply the ensuing results to the study of sequences of submanifolds of symplectic and contact manifolds. This allows us to study the subtle interaction between the Hausdorff metric and the Lagrangian Hofer and spectral metrics. In the process, we get proofs of metric versions of the nearby Lagrangian conjecture and of the Viterbo conjecture on the spectral norm. We also get -rigidity results for a vast class of important submanifolds of symplectic and contact manifolds in the presence of Riemannian bounds. Likewise, we get a Lagrangian generalization of results of Hofer [19] and Viterbo [42] on simultaneous and Hofer/spectral limits — even without any such bounds.
{"title":"Hausdorff limits of submanifolds of symplectic and contact manifolds","authors":"Jean-Philippe Chassé","doi":"10.1016/j.difgeo.2024.102123","DOIUrl":"https://doi.org/10.1016/j.difgeo.2024.102123","url":null,"abstract":"<div><p>We study sequences of immersions respecting bounds coming from Riemannian geometry and apply the ensuing results to the study of sequences of submanifolds of symplectic and contact manifolds. This allows us to study the subtle interaction between the Hausdorff metric and the Lagrangian Hofer and spectral metrics. In the process, we get proofs of metric versions of the nearby Lagrangian conjecture and of the Viterbo conjecture on the spectral norm. We also get <span><math><msup><mrow><mi>C</mi></mrow><mrow><mn>0</mn></mrow></msup></math></span>-rigidity results for a vast class of important submanifolds of symplectic and contact manifolds in the presence of Riemannian bounds. Likewise, we get a Lagrangian generalization of results of Hofer <span>[19]</span> and Viterbo <span>[42]</span> on simultaneous <span><math><msup><mrow><mi>C</mi></mrow><mrow><mn>0</mn></mrow></msup></math></span> and Hofer/spectral limits — even without any such bounds.</p></div>","PeriodicalId":51010,"journal":{"name":"Differential Geometry and its Applications","volume":"94 ","pages":"Article 102123"},"PeriodicalIF":0.5,"publicationDate":"2024-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0926224524000160/pdfft?md5=e5fec57c1405e3388aff79318f022cc4&pid=1-s2.0-S0926224524000160-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140145245","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-18DOI: 10.1016/j.difgeo.2024.102120
Marco Aldi , Sergio Da Silva , Daniele Grandini
We characterize the vanishing of the shifted Courant-Nijenhuis torsion as the strongest tensorial integrability condition that can be imposed on a skew-symmetric endomorphism of the generalized tangent bundle.
我们将移位库朗-尼延胡斯扭转的消失表征为广义切线束的偏斜对称内变形所能施加的最强张量可整性条件。
{"title":"A note on the shifted Courant-Nijenhuis torsion","authors":"Marco Aldi , Sergio Da Silva , Daniele Grandini","doi":"10.1016/j.difgeo.2024.102120","DOIUrl":"https://doi.org/10.1016/j.difgeo.2024.102120","url":null,"abstract":"<div><p>We characterize the vanishing of the shifted Courant-Nijenhuis torsion as the strongest tensorial integrability condition that can be imposed on a skew-symmetric endomorphism of the generalized tangent bundle.</p></div>","PeriodicalId":51010,"journal":{"name":"Differential Geometry and its Applications","volume":"94 ","pages":"Article 102120"},"PeriodicalIF":0.5,"publicationDate":"2024-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140160508","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 : 2024-03-18DOI: 10.1016/j.difgeo.2024.102124
Mohammad Bagher Kazemi Balgeshir, Shiva Salahvarzi
In this paper, we define and characterize 3-Sasakian statistical manifolds and then investigate statistical submersions from 3-Sasakian statistical manifolds. We prove that invariant statistical submersions from 3-Sasakian statistical manifolds with vertical structure vector fields have 3-Sasakian statistical totally geodesic fibers. Moreover, the base space admits a quaternionic Kähler statistical structure. We construct non-trivial examples to illustrate some results of the paper.
{"title":"On statistical submersions from 3-Sasakian statistical manifolds","authors":"Mohammad Bagher Kazemi Balgeshir, Shiva Salahvarzi","doi":"10.1016/j.difgeo.2024.102124","DOIUrl":"https://doi.org/10.1016/j.difgeo.2024.102124","url":null,"abstract":"<div><p>In this paper, we define and characterize 3-Sasakian statistical manifolds and then investigate statistical submersions from 3-Sasakian statistical manifolds. We prove that invariant statistical submersions from 3-Sasakian statistical manifolds with vertical structure vector fields have 3-Sasakian statistical totally geodesic fibers. Moreover, the base space admits a quaternionic Kähler statistical structure. We construct non-trivial examples to illustrate some results of the paper.</p></div>","PeriodicalId":51010,"journal":{"name":"Differential Geometry and its Applications","volume":"94 ","pages":"Article 102124"},"PeriodicalIF":0.5,"publicationDate":"2024-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140160507","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 : 2024-03-15DOI: 10.1016/j.difgeo.2024.102125
R. Fioresi , A. Marraffa , J. Petkovic
We present a review of known models and a new simple mathematical modelling for border completion in the visual cortex V1 highlighting the striking analogies with bicycle rear wheel motions in the plane.
{"title":"A new perspective on border completion in visual cortex as bicycle rear wheel geodesics paths via sub Riemannian Hamiltonian formalism","authors":"R. Fioresi , A. Marraffa , J. Petkovic","doi":"10.1016/j.difgeo.2024.102125","DOIUrl":"https://doi.org/10.1016/j.difgeo.2024.102125","url":null,"abstract":"<div><p>We present a review of known models and a new simple mathematical modelling for border completion in the visual cortex V1 highlighting the striking analogies with bicycle rear wheel motions in the plane.</p></div>","PeriodicalId":51010,"journal":{"name":"Differential Geometry and its Applications","volume":"94 ","pages":"Article 102125"},"PeriodicalIF":0.5,"publicationDate":"2024-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140134564","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 : 2024-03-13DOI: 10.1016/j.difgeo.2024.102121
Leonardo F. Cavenaghi, Lino Grama
Since the advent of new pairwise non-diffeomorphic structures on smooth manifolds, it has been questioned whether two topologically identical manifolds could admit different geometries. Not surprisingly, physicists have wondered whether a different smooth structure assumption to some classical known model could produce different physical meanings. Motivated by the works [27], [2], [3], [18], in this paper, we inaugurate a very computational manner to produce physical models on classical and exotic spheres that can be built equivariantly, such as the classical Gromoll–Meyer exotic spheres. As first applications, we produce Lorentzian metrics on homeomorphic but not diffeomorphic manifolds that enjoy the same physical properties, such as geodesic completeness, positive Ricci curvature, and compatible time orientation. These constructions can be pulled back to higher models, such as exotic ten spheres bounding spin manifolds, to be approached in forthcoming papers.
{"title":"Gromoll–Meyer's actions and the geometry of (exotic) spacetimes","authors":"Leonardo F. Cavenaghi, Lino Grama","doi":"10.1016/j.difgeo.2024.102121","DOIUrl":"https://doi.org/10.1016/j.difgeo.2024.102121","url":null,"abstract":"<div><p>Since the advent of new pairwise non-diffeomorphic structures on smooth manifolds, it has been questioned whether two topologically identical manifolds could admit different geometries. Not surprisingly, physicists have wondered whether a different smooth structure assumption to some classical known model could produce different physical meanings. Motivated by the works <span>[27]</span>, <span>[2]</span>, <span>[3]</span>, <span>[18]</span>, in this paper, we inaugurate a very computational manner to produce physical models on classical and exotic spheres that can be built equivariantly, such as the classical Gromoll–Meyer exotic spheres. As first applications, we produce Lorentzian metrics on homeomorphic but not diffeomorphic manifolds that enjoy the same physical properties, such as geodesic completeness, positive Ricci curvature, and compatible time orientation. These constructions can be pulled back to higher models, such as exotic ten spheres bounding spin manifolds, to be approached in forthcoming papers.</p></div>","PeriodicalId":51010,"journal":{"name":"Differential Geometry and its Applications","volume":"94 ","pages":"Article 102121"},"PeriodicalIF":0.5,"publicationDate":"2024-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140123176","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 : 2024-03-12DOI: 10.1016/j.difgeo.2024.102122
Meher Abdaoui
In this paper, we'll introduce the concept of sympathetic Lie conformal superalgebras and show that some classical properties of Lie conformal superalgebras are still valid for sympathetic Lie conformal superalgebras. We prove that the unique decomposition of each sympathetic Lie conformal superalgebra into a direct sum of indecomposable sympathetic ideals. We also show the existence of a greatest sympathetic ideal and a sympathetic decomposition in every perfect Lie conformal superalgebra. In the end, we also study the ideal of a Lie conformal superalgebra such that is a sympathetic Lie conformal superalgebra.
{"title":"Structures of sympathetic Lie conformal superalgebras","authors":"Meher Abdaoui","doi":"10.1016/j.difgeo.2024.102122","DOIUrl":"https://doi.org/10.1016/j.difgeo.2024.102122","url":null,"abstract":"<div><p>In this paper, we'll introduce the concept of sympathetic Lie conformal superalgebras and show that some classical properties of Lie conformal superalgebras are still valid for sympathetic Lie conformal superalgebras. We prove that the unique decomposition of each sympathetic Lie conformal superalgebra into a direct sum of indecomposable sympathetic ideals. We also show the existence of a greatest sympathetic ideal and a sympathetic decomposition in every perfect Lie conformal superalgebra. In the end, we also study the ideal <span><math><mi>I</mi></math></span> of a Lie conformal superalgebra <span><math><mi>R</mi></math></span> such that <span><math><mi>R</mi><mo>/</mo><mi>I</mi></math></span> is a sympathetic Lie conformal superalgebra.</p></div>","PeriodicalId":51010,"journal":{"name":"Differential Geometry and its Applications","volume":"94 ","pages":"Article 102122"},"PeriodicalIF":0.5,"publicationDate":"2024-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140104001","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}