Applying the systematic method about how to get the discrete counterparts of continuous system given by K. Wu et al., we define the discrete analogue of Ehresmann connections, Cartan connections, and affine connection...Applying the systematic method about how to get the discrete counterparts of continuous system given by K. Wu et al., we define the discrete analogue of Ehresmann connections, Cartan connections, and affine connections in the sense of Koszul and Levi-Civita, and prove some basic properties.展开更多
Within framework of zero curvature representation theory, a family of integrable rational semi-discrete systems is derived from a matrix spectral problem. The Hamiltonian forms of obtained semi-discrete systems are co...Within framework of zero curvature representation theory, a family of integrable rational semi-discrete systems is derived from a matrix spectral problem. The Hamiltonian forms of obtained semi-discrete systems are constructed by means of the discrete trace identity. The Liouville integrability for the obtained family is demonstrated. In the end, a reduced family of obtained semi-discrete systems and its Hamiltonian form are worked out.展开更多
An algebraic structure of discrete zero curvature equations is established for integrable coupling systems associated with semi-direct sums of Lie algebras. As an application example of this algebraic structure, a τ-...An algebraic structure of discrete zero curvature equations is established for integrable coupling systems associated with semi-direct sums of Lie algebras. As an application example of this algebraic structure, a τ-symmetry algebra for the Volterra lattice integrable couplings is engendered from this theory.展开更多
Two hierarchies of nonlinear integrable positive and negative lattice equations are derived from a discrete spectrak problem. The two lattice hierarchies are proved to have discrete zero curvature representations asso...Two hierarchies of nonlinear integrable positive and negative lattice equations are derived from a discrete spectrak problem. The two lattice hierarchies are proved to have discrete zero curvature representations associated with a discrete spectral problem, which also shows that the positive and negative hierarchies correspond to positive and negative power expansions of Lax operators with respect to the spectral parameter, respectively. Moreover, the integrable lattice models in the positive hierarchy are of polynomial type, and the integrable lattice models in the negative hierarchy are of rational type. Further, we construct infinite conservation laws about the positive hierarchy.展开更多
We analyze three commonly used energy functions in solving Plateau-Mesh Prob- lem, that is, Dirichlet, area, and the discrete mean curvature（DMC）. They all possess unique advantages compared to others, but their dra...We analyze three commonly used energy functions in solving Plateau-Mesh Prob- lem, that is, Dirichlet, area, and the discrete mean curvature（DMC）. They all possess unique advantages compared to others, but their drawbacks restrict their usages individually. Our algo- rithm combines the three steps together to make full use of their features. At first the Dirichlet energy is optimized for faster approximation with better topology. Then the area energy is used to come close to the constrained domain. Finally the DMC energy is engaged to achieve a better converging step. Results show that our method can work under a rather noisy initial mesh, which is even topologically different from the final result.展开更多
By considering （2＋1）-dimensional non-isospectral discrete zero curvature equation, the （2＋1）-dimensional non-isospectral Toda lattice hierarchy is constructed in this article. It follows that some reductions of ...By considering （2＋1）-dimensional non-isospectral discrete zero curvature equation, the （2＋1）-dimensional non-isospectral Toda lattice hierarchy is constructed in this article. It follows that some reductions of the （2＋1）- dimensional Toda lattice hierarchy are given. Finally, the （2＋1）-dimensional integrable coupling system of the Toda lattice hierarchy is obtained through enlarging spectral problem.展开更多
New family of integrable symplectic maps are reduced from the Toda hierarchy via constraint for a higher flow of the hierarchy in terms of square eigenfunctions.Their integrability and Lax representation are deduced s...New family of integrable symplectic maps are reduced from the Toda hierarchy via constraint for a higher flow of the hierarchy in terms of square eigenfunctions.Their integrability and Lax representation are deduced systematically from the discrete zero curvature representation of the Toda hierarchy. Also a discrete zero curvature representation for the Toda hierarchy with sources is presented.展开更多
基金National Natural Science Foundation of China under Grant No.10471143National Key Basic Research Project of China under Grant No.2004CB318001
文摘Applying the systematic method about how to get the discrete counterparts of continuous system given by K. Wu et al., we define the discrete analogue of Ehresmann connections, Cartan connections, and affine connections in the sense of Koszul and Levi-Civita, and prove some basic properties.
基金Supported by the Science and Technology Plan Projects of the Educational Department of Shandong Province of China under Grant No. J08LI08
文摘Within framework of zero curvature representation theory, a family of integrable rational semi-discrete systems is derived from a matrix spectral problem. The Hamiltonian forms of obtained semi-discrete systems are constructed by means of the discrete trace identity. The Liouville integrability for the obtained family is demonstrated. In the end, a reduced family of obtained semi-discrete systems and its Hamiltonian form are worked out.
基金supported by the National Key Basic Research Project of China (Grant No. 2004CB318000)the Research Foundation of Hubei Provincial Department of Education (Grant No. D20082602)
文摘An algebraic structure of discrete zero curvature equations is established for integrable coupling systems associated with semi-direct sums of Lie algebras. As an application example of this algebraic structure, a τ-symmetry algebra for the Volterra lattice integrable couplings is engendered from this theory.
基金supported by the "Chunlei" Project of Shandong University of Science and Technology of China under Grant No. 2008BWZ070
文摘Two hierarchies of nonlinear integrable positive and negative lattice equations are derived from a discrete spectrak problem. The two lattice hierarchies are proved to have discrete zero curvature representations associated with a discrete spectral problem, which also shows that the positive and negative hierarchies correspond to positive and negative power expansions of Lax operators with respect to the spectral parameter, respectively. Moreover, the integrable lattice models in the positive hierarchy are of polynomial type, and the integrable lattice models in the negative hierarchy are of rational type. Further, we construct infinite conservation laws about the positive hierarchy.
基金Supported by the National Natural Science Foundation of China(11371320)Zhejiang Natural Science Foundation(LZ14A010002)+1 种基金Foundation of Science and Technology Department of Zhejiang Province(2013C31084)Scientific Research Fund of Zhejiang Provincial Education Department(Y201431077 and Y201329420)
文摘We analyze three commonly used energy functions in solving Plateau-Mesh Prob- lem, that is, Dirichlet, area, and the discrete mean curvature（DMC）. They all possess unique advantages compared to others, but their drawbacks restrict their usages individually. Our algo- rithm combines the three steps together to make full use of their features. At first the Dirichlet energy is optimized for faster approximation with better topology. Then the area energy is used to come close to the constrained domain. Finally the DMC energy is engaged to achieve a better converging step. Results show that our method can work under a rather noisy initial mesh, which is even topologically different from the final result.
基金supported by the State Key Basic Research Development Program of China under Grant No.2004CB318000
文摘By considering （2＋1）-dimensional non-isospectral discrete zero curvature equation, the （2＋1）-dimensional non-isospectral Toda lattice hierarchy is constructed in this article. It follows that some reductions of the （2＋1）- dimensional Toda lattice hierarchy are given. Finally, the （2＋1）-dimensional integrable coupling system of the Toda lattice hierarchy is obtained through enlarging spectral problem.
文摘New family of integrable symplectic maps are reduced from the Toda hierarchy via constraint for a higher flow of the hierarchy in terms of square eigenfunctions.Their integrability and Lax representation are deduced systematically from the discrete zero curvature representation of the Toda hierarchy. Also a discrete zero curvature representation for the Toda hierarchy with sources is presented.
