摘要
Let （?） be the space of C’ vector fields defined on a 2-dimensional closed differentiable manifold M2 endowed with the C’ topology. Let ∑’ denote the set of all structurally stable vector fields. The complement （?）1=（?）’-∑’, is called the bifurcation set. In order to study （?）1, in [1] Andronov and Leontovitch first introduced Definition 1 below and studied the properties of dynamical systems of
