By using the simplified method of factorization given by Valli, and the correspondence between the harmonic map φ∶S 2→U(N) and U(N) uniton bundle ν(φ) with energy corresponding to the bundles’ seco...By using the simplified method of factorization given by Valli, and the correspondence between the harmonic map φ∶S 2→U(N) and U(N) uniton bundle ν(φ) with energy corresponding to the bundles’ second Chern class, which is established by Anand, the energy in a case φ∶S 2→U(N) is investigated in order to estimate the energy of a uniton using the uniton number. It is proved that Uhlenbeck’s factorization is energy decreasing. And a method of estimating the energy of a uniton by the uniton number is given.展开更多
Some new factorizations of unitons into Lie groups are established via singular Darboux transformations. The factorization processes for Grassmannian unitons are also considered. Furthermore, a purely algebraic method...Some new factorizations of unitons into Lie groups are established via singular Darboux transformations. The factorization processes for Grassmannian unitons are also considered. Furthermore, a purely algebraic method for constructing Grassmannian unitons is presented.展开更多
The authors give an algebraic method to add uniton numbers for harmonic maps from a simply connected domain ? ? R2∪{∞} into the unitary group U(N) with ?nite uniton number. So, it is proved that any n-uniton can be ...The authors give an algebraic method to add uniton numbers for harmonic maps from a simply connected domain ? ? R2∪{∞} into the unitary group U(N) with ?nite uniton number. So, it is proved that any n-uniton can be obtained from a 0-uniton by purely algebraic operations and integral transforms to solve the ?ˉ-problem via two different ways.展开更多
The factorization of harmonic maps from a simply-connected domain to the unitary group is studied, showing that the theory of isotropic harmonic maps is equivalent to that of 2-unitons. Furthermore, a positive answer ...The factorization of harmonic maps from a simply-connected domain to the unitary group is studied, showing that the theory of isotropic harmonic maps is equivalent to that of 2-unitons. Furthermore, a positive answer is given to the Uhlenbeck’s conjecture on the upper bound of minimal uniton numbers.展开更多
Is the paper [2] the authors defined the singular Darboux transformations and established an explicit formula for constructing unitons from a simply connected Riemann surface. M to the group U(N). The formula is obtai...Is the paper [2] the authors defined the singular Darboux transformations and established an explicit formula for constructing unitons from a simply connected Riemann surface. M to the group U(N). The formula is obtained as a limit of an infinite consequence of Darboux transformations through some renormalization procedure. In the present paper the authors give a complete proof of the fact that the formula gives a global solution of harmonic maps without singularity.展开更多
We present a unified method for constructing generalized flag transformations of unitons intoa Lie group G via singular Darboux transformations. These flag transformations provide the possibility toestablish some fact...We present a unified method for constructing generalized flag transformations of unitons intoa Lie group G via singular Darboux transformations. These flag transformations provide the possibility toestablish some factorizations for G-unitons.展开更多
文摘By using the simplified method of factorization given by Valli, and the correspondence between the harmonic map φ∶S 2→U(N) and U(N) uniton bundle ν(φ) with energy corresponding to the bundles’ second Chern class, which is established by Anand, the energy in a case φ∶S 2→U(N) is investigated in order to estimate the energy of a uniton using the uniton number. It is proved that Uhlenbeck’s factorization is energy decreasing. And a method of estimating the energy of a uniton by the uniton number is given.
基金Project supported by the Chinese National Research Project"Nonlinear Science",the Scientific Foundation of the National Education Commission of China and the Research Foundation of the Education Commission of Shanghai,the National Natural Science Foundat
文摘Some new factorizations of unitons into Lie groups are established via singular Darboux transformations. The factorization processes for Grassmannian unitons are also considered. Furthermore, a purely algebraic method for constructing Grassmannian unitons is presented.
基金Project supported by the National Natural Science Foundation of China (No.12071106) and the Science Foundation of the Ministry of Education of China.
文摘The authors give an algebraic method to add uniton numbers for harmonic maps from a simply connected domain ? ? R2∪{∞} into the unitary group U(N) with ?nite uniton number. So, it is proved that any n-uniton can be obtained from a 0-uniton by purely algebraic operations and integral transforms to solve the ?ˉ-problem via two different ways.
基金supported by the National Natural Science Foundation of China Natural Science Foundation of Zhejiang Province.
文摘The factorization of harmonic maps from a simply-connected domain to the unitary group is studied, showing that the theory of isotropic harmonic maps is equivalent to that of 2-unitons. Furthermore, a positive answer is given to the Uhlenbeck’s conjecture on the upper bound of minimal uniton numbers.
基金he Special Funds for Major State Basic Ressarch Project of China (NonlinearScience), the National Natural Science Foundation o
文摘Is the paper [2] the authors defined the singular Darboux transformations and established an explicit formula for constructing unitons from a simply connected Riemann surface. M to the group U(N). The formula is obtained as a limit of an infinite consequence of Darboux transformations through some renormalization procedure. In the present paper the authors give a complete proof of the fact that the formula gives a global solution of harmonic maps without singularity.
基金This work wassupported by the National Natural Science Foundation of China (Grant Nos. 19971075 and 10131020), SFZP and Lab. of Math, for Nonlinear Science, Fudan Univ.
文摘We present a unified method for constructing generalized flag transformations of unitons intoa Lie group G via singular Darboux transformations. These flag transformations provide the possibility toestablish some factorizations for G-unitons.
