Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Ising model on nonorientable surfaces: Exact solution for the Moebius
  strip and the Klein bottle   Closed-form expressions are obtained for the partition function of the Ising
model on an M x N simple-quartic lattice embedded on a Moebius strip and a
Klein bottle for finite M and N. The finite-size effects at criticality are
analyzed and compared with those under cylindrical and toroidal boundary
conditions. Our analysis confirms that the central charge is c=1/2.

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The categories of this paper are: quant-ph
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The categories of this paper are: chem-ph
27
The categories of this paper are: comp-gas
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The categories of this paper are: acc-phys
33
The categories of this paper are: plasm-ph
28
The categories of this paper are: alg-geom
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The categories of this paper are: hep-lat
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The categories of this paper are: adap-org
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The categories of this paper are: stat
1
The categories of this paper are: cs
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The categories of this paper are: bayes-an
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The categories of this paper are: solv-int
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The categories of this paper are: econ
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The categories of this paper are: nucl-ex
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The categories of this paper are: atom-ph
37
The categories of this paper are: supr-con