In this paper,we study the value distribution properties of the generalized Gauss maps of weakly complete harmonic surfaces immersed in R^(m),which is the case where the generalized Gauss mapΦis ramified over a famil...In this paper,we study the value distribution properties of the generalized Gauss maps of weakly complete harmonic surfaces immersed in R^(m),which is the case where the generalized Gauss mapΦis ramified over a family of hypersurfaces{Q_(j)}_(j=1)^(q)in P^(m-1)(C)located in the N-subgeneral position.In addition,we investigate the Gauss curvature estimate for the K-quasiconformal harmonic surfaces immersed in R^(3)whose Gauss maps are ramified over a family of hypersurfaces located in the N-subgeneral position.展开更多
Some properties of the pseudo umbilical surface M in R 4 are discussed and thus the lower for the tolal mean curvature of M is estimated. On the basis of the estimation and by using the Gauss map of M...Some properties of the pseudo umbilical surface M in R 4 are discussed and thus the lower for the tolal mean curvature of M is estimated. On the basis of the estimation and by using the Gauss map of M , a sufficient condition is given for M as a flat torus in R 4 .展开更多
Motivated by the result of Chen-Liu-Ru[1],we investigate the value distribution properties for the generalized Gauss maps of weakly complete harmonic surfaces immersed in R^(n) with ramification,which can be seen as a...Motivated by the result of Chen-Liu-Ru[1],we investigate the value distribution properties for the generalized Gauss maps of weakly complete harmonic surfaces immersed in R^(n) with ramification,which can be seen as a generalization of the results in the case of the minimal surfaces.In addition,we give an estimate of the Gauss curvature for the K-quasiconfomal harmonic surfaces whose generalized Gauss map is ramified over a set of hyperplanes.展开更多
Let M be an oriented surface and G(2,k) be the Grassmannian.Smooth maps t1 M→G2（2，k) are studied to determine whether or not they are Gauss maps.Some new results have been obtained and some known results reproved.
The author obtains a Weierstrass representation for surfaces with prescribed normal Gauss map and Gauss curvature in H3. A differential equation about the hyperbolic Gauss map is also obtained, which characterizes the...The author obtains a Weierstrass representation for surfaces with prescribed normal Gauss map and Gauss curvature in H3. A differential equation about the hyperbolic Gauss map is also obtained, which characterizes the relation among the hyperbolic Gauss map, the normal Gauss map and Gauss curvature. The author discusses the harmonicity of the normal Gauss map and the hyperbolic Gauss map from surface with constant Gauss curvature in H3 to S2 with certain altered conformal metric.Finally, the author considers the surface whose normal Gauss map is conformal and derives a completely nonlinear differential equation of second order which graph must satisfy.展开更多
In this paper, the author uses Gauss map to study the topology, volume and diameter of submanifolds in a sphere. It is proved that if there exist ε, 1≥ε > 0 and a fixed unit simple p-vector a such that the Gauss...In this paper, the author uses Gauss map to study the topology, volume and diameter of submanifolds in a sphere. It is proved that if there exist ε, 1≥ε > 0 and a fixed unit simple p-vector a such that the Gauss map g of an n-dimensional complete and connected submanifold M in Sn+p satisfies (g, a) ≥ε, then M is diffeomorphic to Sn, and the volume and diameter of M satisfy εnvol(Sn) ≤vol(M) ≤ vol(Sn)/ε and επ ≤diam(M) ≤ π/ε, respectively. The author also characterizes the case where these inequalities become equalities. As an application, a differential sphere theorem for compact submanifolds in a sphere is obtained.展开更多
The relationship between CR submanifolds in a sphere and their Gauss maps are investigated.Let V be the image of a sphere by a rational holomorphic map F with degree two in another sphere.It is show that the Gauss map...The relationship between CR submanifolds in a sphere and their Gauss maps are investigated.Let V be the image of a sphere by a rational holomorphic map F with degree two in another sphere.It is show that the Gauss map of V is degenerate if and only if F is linear fractional.展开更多
In this paper we study surfaces in S^4 and their twistor Gauss maps.Some necessary and sufficient conditions that the twistor Gauss map is harmonic are given.We find many examples of nonisotropic harmonic maps from a ...In this paper we study surfaces in S^4 and their twistor Gauss maps.Some necessary and sufficient conditions that the twistor Gauss map is harmonic are given.We find many examples of nonisotropic harmonic maps from a surface to(?)P^3.展开更多
This paper studies the Gauss map of submanifolds in space forms defined by Willmore andSaleemi. By using Morse functions,it is proved that the degree of Gauss map is the Eulernumber of the submanifold.The tight immers...This paper studies the Gauss map of submanifolds in space forms defined by Willmore andSaleemi. By using Morse functions,it is proved that the degree of Gauss map is the Eulernumber of the submanifold.The tight immersions are also studied.展开更多
Demoulin surfaces in the real projective 3-space are investigated. Our result enables us to establish a generalized Weierstrass type representation for definite Demoulin surfaces by virtue of primitive maps into a cer...Demoulin surfaces in the real projective 3-space are investigated. Our result enables us to establish a generalized Weierstrass type representation for definite Demoulin surfaces by virtue of primitive maps into a certain semi-Riemannian 6-symmetric space.展开更多
Gauss maps of oriented timelike 2-surfaces in are characterized, and it is shown that Gallss maps can determine surfaces locally as they do in case. Moreover, some essential differences are discovered between the prop...Gauss maps of oriented timelike 2-surfaces in are characterized, and it is shown that Gallss maps can determine surfaces locally as they do in case. Moreover, some essential differences are discovered between the properties of the Gauss maps of surfaces in Rn and those of the Gauss maps of timelike surfaces in. In particular, a counterexample shows that a nonminimal timelike surface in cannot be essentially determined by its Gauss map.展开更多
基金supported by the NFSC(11971182,12271189)the NFS of Fujian Province of China(2019J01066,2021J01304)。
文摘In this paper,we study the value distribution properties of the generalized Gauss maps of weakly complete harmonic surfaces immersed in R^(m),which is the case where the generalized Gauss mapΦis ramified over a family of hypersurfaces{Q_(j)}_(j=1)^(q)in P^(m-1)(C)located in the N-subgeneral position.In addition,we investigate the Gauss curvature estimate for the K-quasiconformal harmonic surfaces immersed in R^(3)whose Gauss maps are ramified over a family of hypersurfaces located in the N-subgeneral position.
文摘Some properties of the pseudo umbilical surface M in R 4 are discussed and thus the lower for the tolal mean curvature of M is estimated. On the basis of the estimation and by using the Gauss map of M , a sufficient condition is given for M as a flat torus in R 4 .
基金supported by the Fundamental Research Funds for the Central Universities(500421360)supported by NNSF of China(11571049,12071047)+1 种基金supported by NNSF of China(11971182)NSF of Fujian Province of China(2019J01066)。
文摘Motivated by the result of Chen-Liu-Ru[1],we investigate the value distribution properties for the generalized Gauss maps of weakly complete harmonic surfaces immersed in R^(n) with ramification,which can be seen as a generalization of the results in the case of the minimal surfaces.In addition,we give an estimate of the Gauss curvature for the K-quasiconfomal harmonic surfaces whose generalized Gauss map is ramified over a set of hyperplanes.
文摘Let M be an oriented surface and G(2,k) be the Grassmannian.Smooth maps t1 M→G2（2，k) are studied to determine whether or not they are Gauss maps.Some new results have been obtained and some known results reproved.
基金Project supported by the 973 Project of the Ministry of Science and Technology of China and the Science Foundation of the Ministry of Education of China.
文摘The author obtains a Weierstrass representation for surfaces with prescribed normal Gauss map and Gauss curvature in H3. A differential equation about the hyperbolic Gauss map is also obtained, which characterizes the relation among the hyperbolic Gauss map, the normal Gauss map and Gauss curvature. The author discusses the harmonicity of the normal Gauss map and the hyperbolic Gauss map from surface with constant Gauss curvature in H3 to S2 with certain altered conformal metric.Finally, the author considers the surface whose normal Gauss map is conformal and derives a completely nonlinear differential equation of second order which graph must satisfy.
基金Project supported by the Fund of the Education Department of Zhejiang Province of China (No.20030707).
文摘In this paper, the author uses Gauss map to study the topology, volume and diameter of submanifolds in a sphere. It is proved that if there exist ε, 1≥ε > 0 and a fixed unit simple p-vector a such that the Gauss map g of an n-dimensional complete and connected submanifold M in Sn+p satisfies (g, a) ≥ε, then M is diffeomorphic to Sn, and the volume and diameter of M satisfy εnvol(Sn) ≤vol(M) ≤ vol(Sn)/ε and επ ≤diam(M) ≤ π/ε, respectively. The author also characterizes the case where these inequalities become equalities. As an application, a differential sphere theorem for compact submanifolds in a sphere is obtained.
文摘The relationship between CR submanifolds in a sphere and their Gauss maps are investigated.Let V be the image of a sphere by a rational holomorphic map F with degree two in another sphere.It is show that the Gauss map of V is degenerate if and only if F is linear fractional.
基金Supported by the National Natural Science Foundation of China and the Science Foundation of Zhejiang Province.
文摘In this paper we study surfaces in S^4 and their twistor Gauss maps.Some necessary and sufficient conditions that the twistor Gauss map is harmonic are given.We find many examples of nonisotropic harmonic maps from a surface to(?)P^3.
文摘This paper studies the Gauss map of submanifolds in space forms defined by Willmore andSaleemi. By using Morse functions,it is proved that the degree of Gauss map is the Eulernumber of the submanifold.The tight immersions are also studied.
基金supported by JSPS KAKENHI (Grant Nos. JP18K03265 and JP19K03461)。
文摘Demoulin surfaces in the real projective 3-space are investigated. Our result enables us to establish a generalized Weierstrass type representation for definite Demoulin surfaces by virtue of primitive maps into a certain semi-Riemannian 6-symmetric space.
文摘Gauss maps of oriented timelike 2-surfaces in are characterized, and it is shown that Gallss maps can determine surfaces locally as they do in case. Moreover, some essential differences are discovered between the properties of the Gauss maps of surfaces in Rn and those of the Gauss maps of timelike surfaces in. In particular, a counterexample shows that a nonminimal timelike surface in cannot be essentially determined by its Gauss map.
