Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Twisted equivariant K-theory, groupoids and proper actions   In this paper we define twisted equivariant K-theory for actions of Lie
groupoids. For a Bredon-compatible Lie groupoid, this defines a periodic
cohomology theory on the category of finite CW-complexes with equivariant
stable projective bundles. A classification of these bundles is shown. We also
obtain a completion theorem and apply these results to proper actions of
groups.

25
The categories of this paper are: patt-sol
34
The categories of this paper are: chem-ph
20
The categories of this paper are: acc-phys
13
The categories of this paper are: quant-ph
35
The categories of this paper are: mtrl-th
6
The categories of this paper are: astro-ph
15
The categories of this paper are: nucl-ex
14
The categories of this paper are: math-ph
36
The categories of this paper are: cmp-lg
10
The categories of this paper are: q-bio
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The categories of this paper are: alg-geom
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The categories of this paper are: chao-dyn
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The categories of this paper are: stat
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The categories of this paper are: funct-an
11
The categories of this paper are: hep-lat
27
The categories of this paper are: comp-gas