Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Counting the Angels and Devils in Escher's Circle Limit IV   We derive the rational generating function that enumerates the angels and
devils in M. C. Escher's {\it Circle Limit IV} according to their combinatorial
distance from the six creatures whose feet meet at the center of the disk. This
result shows that the base of the exponential rate of growth is $1.582\ldots$
(the largest root of the polynomial $1 - z^2 - 2z^3 - z^4 + z^6$).

27
The categories of this paper are: comp-gas
8
The categories of this paper are: hep-ex
4
The categories of this paper are: cond-mat
26
The categories of this paper are: bayes-an
21
The categories of this paper are: adap-org
7
The categories of this paper are: hep-th
29
The categories of this paper are: funct-an
36
The categories of this paper are: cmp-lg
20
The categories of this paper are: acc-phys
9
The categories of this paper are: nlin
17
The categories of this paper are: q-fin
10
The categories of this paper are: q-bio
6
The categories of this paper are: astro-ph
0
The categories of this paper are: hep-ph
31
The categories of this paper are: ao-sci
35
The categories of this paper are: mtrl-th