Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Good Wannier bases in Hilbert modules associated to topological
  insulators   For a large class of physically relevant operators on a manifold with
discrete group action, we prove general results on the (non-)existence of a
basis of smooth well-localised Wannier functions for their spectral subspaces.
This turns out to be equivalent to the freeness of a certain Hilbert module
over the group $C^*$-algebra canonically associated to the spectral subspace.
This brings into play $K$-theoretic methods and justifies their importance as
invariants of topological insulators in physics.

22
The categories of this paper are: chao-dyn
12
The categories of this paper are: nucl-th
19
The categories of this paper are: eess
24
The categories of this paper are: dg-ga
34
The categories of this paper are: chem-ph
23
The categories of this paper are: solv-int
28
The categories of this paper are: alg-geom
13
The categories of this paper are: quant-ph
31
The categories of this paper are: ao-sci
27
The categories of this paper are: comp-gas
3
The categories of this paper are: physics
21
The categories of this paper are: adap-org
6
The categories of this paper are: astro-ph
33
The categories of this paper are: plasm-ph
1
The categories of this paper are: cs
7
The categories of this paper are: hep-th