Hello all.
Consider the torus T^2 as a subset of R^3, for example the inverse image of 0 by the function f(x,y,z)=(\sqrt{x^2+y^2}-1)^2+z^2-4.
I need to obtain a example of a vector field X defined in the whole R^3, such that:
1) X is invariant in the torus
2) the orbits of X in the torus are...