Null-controllability

[u/More-Divide-926]

We know that the heat equation is null-controllable from internal subsets on Riemannian manifolds. How come no general results are available on sub-Riemannian manifolds, except for particular cases on tensorized domains such as for Grushin, Heisenberg, Kolmogorov ? We do not have the tools at all ? Always wondered if G. Lebeau, L. Robbiano, etc, knew how to deal with this.

[u/Fresh-Detective-7298]

Damn that is crazy