Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The Perturbative Calculation of the Spin-Spin Correlation Function in
  the Two Dimensional Ising Model   Using the variational formula for operator product coefficients a method for
perturbative calculation of the short-distance expansion of the Spin-Spin
correlation function in the two dimensional Ising model is presented. Results
of explicit calculation up to third order agree with known results from the
scaling limit of the lattice calculation.

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The categories of this paper are: dg-ga
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The categories of this paper are: math-ph
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The categories of this paper are: solv-int
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The categories of this paper are: adap-org
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The categories of this paper are: econ
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The categories of this paper are: hep-lat
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The categories of this paper are: physics
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The categories of this paper are: alg-geom
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The categories of this paper are: chem-ph
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The categories of this paper are: mtrl-th
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The categories of this paper are: astro-ph
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The categories of this paper are: hep-ex
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The categories of this paper are: nlin
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The categories of this paper are: eess
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The categories of this paper are: q-fin
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The categories of this paper are: quant-ph