The generalized conditional symmetry and sign-invariant approaches are developed to study the nonlinear diffusion equations with x-dependent convection and source terms. We obtain conditions under which the equations ...The generalized conditional symmetry and sign-invariant approaches are developed to study the nonlinear diffusion equations with x-dependent convection and source terms. We obtain conditions under which the equations admit the second-order generalized conditional symmetries and the first-order sign-invariants on the solutions. Several types of different generalized conditional symmetries and first-order sign-invariants for the equations with diffusion of power law are obtained. Exact solutions to the resulting equations are constructed.展开更多
Abstract homomorphisms between subgroups of algebraic groups were studied in detail by A.Borel, J.Tit.[1] and B.Wei.feile.[2] provided that the images of the homomorphisms are Zariski dense subsets and that the fields...Abstract homomorphisms between subgroups of algebraic groups were studied in detail by A.Borel, J.Tit.[1] and B.Wei.feile.[2] provided that the images of the homomorphisms are Zariski dense subsets and that the fields over which algebraic groups are defined are infinite. The purpose of this paper is to determine all embedding homomorphisms of SLn(k) into SLn(K) when k and K are any fields of the same characteristic, without assumption of Zariski density and infinitude of fields. The result in this paper generalizes a result of Chen Yu on homomorphisms of two dimensional linear groups[3].展开更多
基金The project supported in part by National Natural Science Foundation of China under Grant No.19901027the Natural Science Foundation of Shaanxi Province of China
文摘The generalized conditional symmetry and sign-invariant approaches are developed to study the nonlinear diffusion equations with x-dependent convection and source terms. We obtain conditions under which the equations admit the second-order generalized conditional symmetries and the first-order sign-invariants on the solutions. Several types of different generalized conditional symmetries and first-order sign-invariants for the equations with diffusion of power law are obtained. Exact solutions to the resulting equations are constructed.
文摘Abstract homomorphisms between subgroups of algebraic groups were studied in detail by A.Borel, J.Tit.[1] and B.Wei.feile.[2] provided that the images of the homomorphisms are Zariski dense subsets and that the fields over which algebraic groups are defined are infinite. The purpose of this paper is to determine all embedding homomorphisms of SLn(k) into SLn(K) when k and K are any fields of the same characteristic, without assumption of Zariski density and infinitude of fields. The result in this paper generalizes a result of Chen Yu on homomorphisms of two dimensional linear groups[3].
