In the theory of dynamical systems, Peixoto theorem, proved by MaurĂcio Peixoto, states that among all smooth flows on surfaces, i.e. compact two-dimensional manifolds, structurally stable systems may be characterized by the following properties:
Moreover, they form an open set in the space of all flows endowed with C1 topology.
References
Peixoto's theorem Wikipedia(Text) CC BY-SA