We study the limit cycle bifurcations perturbing a class of quartic linear-like Hamiltonian systems having an elementary center at the origin. First, using methods of the qualitative theory, all possible phase portrai...We study the limit cycle bifurcations perturbing a class of quartic linear-like Hamiltonian systems having an elementary center at the origin. First, using methods of the qualitative theory, all possible phase portraits of the unperturbed system are found. Then, using the first order Melnikov function, Hopf bifurcation problem of the perturbed system is investigated, and an upper bound for the function is obtained near the origin.展开更多
Let π be a group with a unit 1; H is a Hopf π- coalgebra and A is a right π-H-comodule algebra. First, the notion of a two-sided relative （A, H）-Hopf π-comodule is introduced; then it is obtained that Hom A H （...Let π be a group with a unit 1; H is a Hopf π- coalgebra and A is a right π-H-comodule algebra. First, the notion of a two-sided relative （A, H）-Hopf π-comodule is introduced; then it is obtained that Hom A H （M, N） H and HOMA（M, N） are isomorphic as right Hopf π-H-comodules, where Hom A H（M, N） denotes the space of right A-module fight H-comodule morphisms and HOMa （M, N） denotes the rational space of a space Hom A（M, N） of right A-module morphisms. Secondly, the structure theorem of endomorphism algebras of two-sided relative （A, H）-Hopf π--comodules is established; that is, End A H （M）#H and END A（M, N） are isomorphic as fight Hopf π-H-comodules and algebras.展开更多
基金supported by the National Natural Science Foundations of China(12371171)and the Natural Science Foundation of Jiangsu Province(BK20221339).
文摘We study the limit cycle bifurcations perturbing a class of quartic linear-like Hamiltonian systems having an elementary center at the origin. First, using methods of the qualitative theory, all possible phase portraits of the unperturbed system are found. Then, using the first order Melnikov function, Hopf bifurcation problem of the perturbed system is investigated, and an upper bound for the function is obtained near the origin.
基金The Research and Innovation Project for College Graduates of Jiangsu Province(No.CXLX_0094)the Natural Science Foundation of Chuzhou University(No.2010kj006Z)
文摘Let π be a group with a unit 1; H is a Hopf π- coalgebra and A is a right π-H-comodule algebra. First, the notion of a two-sided relative （A, H）-Hopf π-comodule is introduced; then it is obtained that Hom A H （M, N） H and HOMA（M, N） are isomorphic as right Hopf π-H-comodules, where Hom A H（M, N） denotes the space of right A-module fight H-comodule morphisms and HOMa （M, N） denotes the rational space of a space Hom A（M, N） of right A-module morphisms. Secondly, the structure theorem of endomorphism algebras of two-sided relative （A, H）-Hopf π--comodules is established; that is, End A H （M）#H and END A（M, N） are isomorphic as fight Hopf π-H-comodules and algebras.
