The GNVW index and its generalizations.

Gross, et. al. defined an index for bosonic “locality preserving”  unitaries which measures net transport of quantum information (left or right). This index has a fermionic generalization (due to Fidkowski et.al.) important in Floquet physics. I will discuss a generalization of this index to higher dimensions where it assumes the form of an incompressible flow. I feel that this generalization is ½-interesting: Some new idea needs to be added to find cool applications, perhaps to knot or manifold invariants. I will seek the advice of the audience.