Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The C*-algebra of the exponential function   The complex exponential function is a local homeomorphism and gives therefore
rise to an 'etale groupoid and a C*-algebra. We determine this algebra, as well
as the alge bra of the complex conjugate of the exponential function.

13
The categories of this paper are: quant-ph
14
The categories of this paper are: math-ph
24
The categories of this paper are: dg-ga
8
The categories of this paper are: hep-ex
22
The categories of this paper are: chao-dyn
35
The categories of this paper are: mtrl-th
10
The categories of this paper are: q-bio
36
The categories of this paper are: cmp-lg
29
The categories of this paper are: funct-an
6
The categories of this paper are: astro-ph
34
The categories of this paper are: chem-ph
9
The categories of this paper are: nlin
37
The categories of this paper are: supr-con
32
The categories of this paper are: atom-ph
20
The categories of this paper are: acc-phys
1
The categories of this paper are: cs