This is the space generated by eigenvector with both positive eigevalues:
And the flow associated is:

Example of a saddle (linear):

  • spans the unstable subspace
  • spans the stable subspace

Example of a non-linear saddle:

  • near to the ss, the linar approximation is tangent to the manyfold
  • As you can see the stable manyfold has the flow that points toward the ss, while for the unstable manyfold the flow points to infinty.
  • The linar approximation is valid only near the ss.

If we draw the flow of the non-linar system:

  • Notice the similiraties with the linear system.
  • In this case is like the linear system, but it is distorted.