This paper aims to study the Berger type deformed Sasaki metric g_(BS)on the second order tangent bundle T^(2)M over a bi-Kählerian manifold M.The authors firstly find the Levi-Civita connection of the Berger typ...This paper aims to study the Berger type deformed Sasaki metric g_(BS)on the second order tangent bundle T^(2)M over a bi-Kählerian manifold M.The authors firstly find the Levi-Civita connection of the Berger type deformed Sasaki metric g_(BS)and calculate all forms of Riemannian curvature tensors of this metric.Also,they study geodesics on the second order tangent bundle T^(2)M and bi-unit second order tangent bundle T^(2)_(1,1)M,and characterize a geodesic of the bi-unit second order tangent bundle in terms of geodesic curvatures of its projection to the base.Finally,they present some conditions for a sectionσ:M→T^(2)M to be harmonic and study the harmonicity of the different canonical projections and inclusions of(T^(2)M,g_(BS)).Moreover,they search the harmonicity of the Berger type deformed Sasaki metric g_(BS)and the Sasaki metric g_(S) with respect to each other.展开更多
Let （M, g） be an n-dimensional Riemannian manifold and T2M be its second- order tangent bundle equipped with a lift metric g. In this paper, first, the authors con- struct some Riemannian almost product structures ...Let （M, g） be an n-dimensional Riemannian manifold and T2M be its second- order tangent bundle equipped with a lift metric g. In this paper, first, the authors con- struct some Riemannian almost product structures on （T2M, g） and present some results concerning these structures. Then, they investigate the curvature properties of （T2M, g）. Finally, they study the properties of two metric connections with nonvanishing torsion on （T2M, g： The//-lift of the Levi-Civita connection of g to TaM, and the product conjugate connection defined by the Levi-Civita connection of g and an almost product structure.展开更多
Let （Mn, g） and （N^n＋1, G） be Riemannian manifolds. Let TMn and TN^n＋1 be the associated tangent bundles. Let f ： （M^n, g） → （N^＋1, G） be an isometrical immersion with g = f^＊G, F = （f, df） ： （TM^n,g...Let （Mn, g） and （N^n＋1, G） be Riemannian manifolds. Let TMn and TN^n＋1 be the associated tangent bundles. Let f ： （M^n, g） → （N^＋1, G） be an isometrical immersion with g = f^＊G, F = （f, df） ： （TM^n,g） → （TN^n＋1, Gs） be the isometrical immersion with g= F＊Gs where （df）x ： TxM → Tf（x）N for any x∈ M is the differential map, and Gs be the Sasaki metric on TN induced from G. This paper deals with the geometry of TM^n as a submanifold of TN^n＋1 by the moving frame method. The authors firstly study the extrinsic geometry of TMn in TN^n＋1. Then the integrability of the induced almost complex structure of TM is discussed.展开更多
Let Y be a smooth projective surface defined over an algebraically closed field k with char k ≠ 2, and let π ： X → Y be a double covering branched along a smooth divisor. We show that Jx is stable with respect to...Let Y be a smooth projective surface defined over an algebraically closed field k with char k ≠ 2, and let π ： X → Y be a double covering branched along a smooth divisor. We show that Jx is stable with respect to π＊H if the tangent bundle Jy is semi-stable with respect to some ample line bundle H on Y.展开更多
We present a differential geometric perspective of the IEP for symmetric matrices in the framework of a fibre bundle with structure group SO（n）. In particular, a Newton type algorithm is developed to construct a non...We present a differential geometric perspective of the IEP for symmetric matrices in the framework of a fibre bundle with structure group SO（n）. In particular, a Newton type algorithm is developed to construct a non singular symmetric matrix for given target eigenvalues using a singular symmetric matrix as the initial matrix for the iteration. Explicit computations are performed for 2 x 2 non singular symmetric matrix to illustrate the result.展开更多
In this paper,we study minimal Legendrian surfacesΣimmersed in the tangent sphere bundle T_(1)R^(3).We classify(1)totally geodesic Legendrian surfaces,(2)closed minimal Legendrian surfaces of genus smaller than or eq...In this paper,we study minimal Legendrian surfacesΣimmersed in the tangent sphere bundle T_(1)R^(3).We classify(1)totally geodesic Legendrian surfaces,(2)closed minimal Legendrian surfaces of genus smaller than or equal to 1 and complete minimal Legendrian surfaces with the non-negative Gauss curvature,and(3)complete stable minimal Legendrian surfaces.展开更多
By applying the framework of the tangent bundle geometry to the method of Lagrange multi- pliers,a geometric description of Chetaev's nonholonomic systems subjected to unilateral nonholonomic con- straints trod un...By applying the framework of the tangent bundle geometry to the method of Lagrange multi- pliers,a geometric description of Chetaev's nonholonomic systems subjected to unilateral nonholonomic con- straints trod unilateral holonomic constraints respectively in time-independent circumstances is presented.展开更多
In this paper,the modern geometrical structure of analytical mechanics,the exterior differential forms and the geometrical meaning of dynamic equations are briefly discussed.
A differentiable manifold is said to be contact if it admits a linear functional f on the tangent bundle satisfying f ∧(df)^(M-1)≠0.This remark obtain the following the classification:Let M be a complete connected c...A differentiable manifold is said to be contact if it admits a linear functional f on the tangent bundle satisfying f ∧(df)^(M-1)≠0.This remark obtain the following the classification:Let M be a complete connected contact hyper-surface of CH^2(-4),then M is congruent to one of the following: (i)A tube of radius r>0 around a totally geodesic,totally real hyperbolic space form H^2(-1); (ii)A tube of radius r>0 around a totally geodesic complex hyperbolic space form CH^1(-4); (iii)A geodesic hypersphere of radius r>0,or (iv)A horosphere.展开更多
In this paper.we discuss Lagrangian vector field on Kahler manifold and use it to describe and solve some problem in Newtonican and Lagrangian Mechanics on Kahler Manifold.
Let X be an irreducible Hermitian symmetric space of compact type(IHSS for short).In this paper,we give the irreducible decomposition of SymrTX.As a by-product,we give a cohomological characterization of the rank of X...Let X be an irreducible Hermitian symmetric space of compact type(IHSS for short).In this paper,we give the irreducible decomposition of SymrTX.As a by-product,we give a cohomological characterization of the rank of X.Moreover,we introduce pseudoeffective thresholds to measure the bigness of tangent bundles of smooth complex projective varieties precisely and calculate them for irreducible Hermitian symmetric spaces of compact type.展开更多
Our previous papers introduce topological notions of normal crossings symplectic divisor and variety,show that they are equivalent,in a suitable sense,to the corresponding geometric notions,and establish a topological...Our previous papers introduce topological notions of normal crossings symplectic divisor and variety,show that they are equivalent,in a suitable sense,to the corresponding geometric notions,and establish a topological smoothability criterion for normal crossings symplectic varieties.The present paper constructs a blowup,a complex line bundle,and a logarithmic tangent bundle naturally associated with a normal crossings symplectic divisor and determines the Chern class of the last bundle.These structures have applications in constructions and analysis of various moduli spaces.As a corollary of the Chern class formula for the logarithmic tangent bundle,we refine Aluffi’s formula for the Chern class of the tangent bundle of the blowup at a complete intersection to account for the torsion and extend it to the blowup at the deepest stratum of an arbitrary normal crossings divisor.展开更多
The main purpose of this paper is to study the differential geometrical objects on tangent bundle corresponding to dual-holomorphic objects of dual-holomorphic manifold.As a result of this approach,the authors find a ...The main purpose of this paper is to study the differential geometrical objects on tangent bundle corresponding to dual-holomorphic objects of dual-holomorphic manifold.As a result of this approach,the authors find a new class of lifts(deformed complete lifts)in the tangent bundle.展开更多
文摘This paper aims to study the Berger type deformed Sasaki metric g_(BS)on the second order tangent bundle T^(2)M over a bi-Kählerian manifold M.The authors firstly find the Levi-Civita connection of the Berger type deformed Sasaki metric g_(BS)and calculate all forms of Riemannian curvature tensors of this metric.Also,they study geodesics on the second order tangent bundle T^(2)M and bi-unit second order tangent bundle T^(2)_(1,1)M,and characterize a geodesic of the bi-unit second order tangent bundle in terms of geodesic curvatures of its projection to the base.Finally,they present some conditions for a sectionσ:M→T^(2)M to be harmonic and study the harmonicity of the different canonical projections and inclusions of(T^(2)M,g_(BS)).Moreover,they search the harmonicity of the Berger type deformed Sasaki metric g_(BS)and the Sasaki metric g_(S) with respect to each other.
文摘Let （M, g） be an n-dimensional Riemannian manifold and T2M be its second- order tangent bundle equipped with a lift metric g. In this paper, first, the authors con- struct some Riemannian almost product structures on （T2M, g） and present some results concerning these structures. Then, they investigate the curvature properties of （T2M, g）. Finally, they study the properties of two metric connections with nonvanishing torsion on （T2M, g： The//-lift of the Levi-Civita connection of g to TaM, and the product conjugate connection defined by the Levi-Civita connection of g and an almost product structure.
基金supported by the National Natural Science Foundation of China(No.61473059)the Fundamental Research Funds for the Central University(No.DUT11LK47)
文摘Let （Mn, g） and （N^n＋1, G） be Riemannian manifolds. Let TMn and TN^n＋1 be the associated tangent bundles. Let f ： （M^n, g） → （N^＋1, G） be an isometrical immersion with g = f^＊G, F = （f, df） ： （TM^n,g） → （TN^n＋1, Gs） be the isometrical immersion with g= F＊Gs where （df）x ： TxM → Tf（x）N for any x∈ M is the differential map, and Gs be the Sasaki metric on TN induced from G. This paper deals with the geometry of TM^n as a submanifold of TN^n＋1 by the moving frame method. The authors firstly study the extrinsic geometry of TMn in TN^n＋1. Then the integrability of the induced almost complex structure of TM is discussed.
文摘Let Y be a smooth projective surface defined over an algebraically closed field k with char k ≠ 2, and let π ： X → Y be a double covering branched along a smooth divisor. We show that Jx is stable with respect to π＊H if the tangent bundle Jy is semi-stable with respect to some ample line bundle H on Y.
文摘We present a differential geometric perspective of the IEP for symmetric matrices in the framework of a fibre bundle with structure group SO（n）. In particular, a Newton type algorithm is developed to construct a non singular symmetric matrix for given target eigenvalues using a singular symmetric matrix as the initial matrix for the iteration. Explicit computations are performed for 2 x 2 non singular symmetric matrix to illustrate the result.
基金supported by National Natural Science Foundation of China(Grant No.11901534)。
文摘In this paper,we study minimal Legendrian surfacesΣimmersed in the tangent sphere bundle T_(1)R^(3).We classify(1)totally geodesic Legendrian surfaces,(2)closed minimal Legendrian surfaces of genus smaller than or equal to 1 and complete minimal Legendrian surfaces with the non-negative Gauss curvature,and(3)complete stable minimal Legendrian surfaces.
基金the National Natural Science Foundation of China(No.19972010)the Qing Lan Project Foundation of Jiangsu Province of Chinathe Research Foundation of Suzhou Institute of Urban Construction & Environmental Protection of China
文摘By applying the framework of the tangent bundle geometry to the method of Lagrange multi- pliers,a geometric description of Chetaev's nonholonomic systems subjected to unilateral nonholonomic con- straints trod unilateral holonomic constraints respectively in time-independent circumstances is presented.
基金Work supported by NSF of Henan Education Commission
文摘In this paper,the modern geometrical structure of analytical mechanics,the exterior differential forms and the geometrical meaning of dynamic equations are briefly discussed.
文摘A differentiable manifold is said to be contact if it admits a linear functional f on the tangent bundle satisfying f ∧(df)^(M-1)≠0.This remark obtain the following the classification:Let M be a complete connected contact hyper-surface of CH^2(-4),then M is congruent to one of the following: (i)A tube of radius r>0 around a totally geodesic,totally real hyperbolic space form H^2(-1); (ii)A tube of radius r>0 around a totally geodesic complex hyperbolic space form CH^1(-4); (iii)A geodesic hypersphere of radius r>0,or (iv)A horosphere.
文摘In this paper.we discuss Lagrangian vector field on Kahler manifold and use it to describe and solve some problem in Newtonican and Lagrangian Mechanics on Kahler Manifold.
文摘Let X be an irreducible Hermitian symmetric space of compact type(IHSS for short).In this paper,we give the irreducible decomposition of SymrTX.As a by-product,we give a cohomological characterization of the rank of X.Moreover,we introduce pseudoeffective thresholds to measure the bigness of tangent bundles of smooth complex projective varieties precisely and calculate them for irreducible Hermitian symmetric spaces of compact type.
基金Supported by NSF grants DMS-2003340(F.Tehrani)DMS-1811861(Mclean)DMS-1901979(Zinger)。
文摘Our previous papers introduce topological notions of normal crossings symplectic divisor and variety,show that they are equivalent,in a suitable sense,to the corresponding geometric notions,and establish a topological smoothability criterion for normal crossings symplectic varieties.The present paper constructs a blowup,a complex line bundle,and a logarithmic tangent bundle naturally associated with a normal crossings symplectic divisor and determines the Chern class of the last bundle.These structures have applications in constructions and analysis of various moduli spaces.As a corollary of the Chern class formula for the logarithmic tangent bundle,we refine Aluffi’s formula for the Chern class of the tangent bundle of the blowup at a complete intersection to account for the torsion and extend it to the blowup at the deepest stratum of an arbitrary normal crossings divisor.
文摘The main purpose of this paper is to study the differential geometrical objects on tangent bundle corresponding to dual-holomorphic objects of dual-holomorphic manifold.As a result of this approach,the authors find a new class of lifts(deformed complete lifts)in the tangent bundle.
