title: The existence of periodic orbits and invariant tori for some 3-dimensional quadratic systems.
abstract: We use the normal form theory, averaging method, and integral manifold theorem to study the existence of limit cycles in Lotka-Volterra systems and the existence of invariant tori in quadratic systems in ℝ(3).
authors: Department of Mathematics, Shanghai Normal University, Shanghai 200234, China.
authors: Yanan
authors: Y
authors: Jiang
authors: Department of Mathematics, Shanghai Normal University, Shanghai 200234, China.
authors: Maoan
authors: M
authors: Han
authors: Department of Mathematics, Shanghai Jiaotong University, Shanghai 200240, China.
authors: Dongmei
authors: D
authors: Xiao
mesh_terms: D000465:Algorithms; D008962:Models, Theoretical