Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: An Exact Result for the Partition Function of Two-Dimensional Nearest
  Neighbour Ising Models in Non-Zero Magnetic Field   The partition function of two-dimensional nearest neighbour Ising models in a
non-zero magnetic field is derived employing a matrix formulation.

29
The categories of this paper are: funct-an
1
The categories of this paper are: cs
17
The categories of this paper are: q-fin
9
The categories of this paper are: nlin
28
The categories of this paper are: alg-geom
36
The categories of this paper are: cmp-lg
26
The categories of this paper are: bayes-an
25
The categories of this paper are: patt-sol
37
The categories of this paper are: supr-con
13
The categories of this paper are: quant-ph
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The categories of this paper are: atom-ph
18
The categories of this paper are: econ
11
The categories of this paper are: hep-lat
12
The categories of this paper are: nucl-th
27
The categories of this paper are: comp-gas
10
The categories of this paper are: q-bio