Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Surface Critical Behavior of Binary Alloys and Antiferromagnets:
  Dependence of the Universality Class on Surface Orientation   The surface critical behavior of semi-infinite
  (a) binary alloys with a continuous order-disorder transition and
  (b) Ising antiferromagnets in the presence of a magnetic field is considered.
In contrast to ferromagnets, the surface universality class of these systems
depends on the orientation of the surface with respect to the crystal axes.
There is ordinary and extraordinary surface critical behavior for orientations
that preserve and break the two-sublattice symmetry, respectively. This is
confirmed by transfer-matrix calculations for the two-dimensional
antiferromagnet and other evidence.

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The categories of this paper are: funct-an
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The categories of this paper are: atom-ph
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The categories of this paper are: nucl-ex
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The categories of this paper are: math-ph
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The categories of this paper are: q-fin
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The categories of this paper are: physics
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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: eess
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The categories of this paper are: dg-ga
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The categories of this paper are: astro-ph
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The categories of this paper are: econ
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The categories of this paper are: q-bio
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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: patt-sol