Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Almost complex structures and calibrated integral cycles in contact
  5-manifolds   In a contact manifold (M^5, alpha), we consider almost complex structures J
which satisfy, for any vector v in the horizontal distribution, d alpha (v,Jv)
= 0. We prove that integral cycles whose approximate tangent planes have the
property of being J-invariant are in fact smooth Legendrian curves except
possibly at isolated points and we investigate how such structures J are
related to calibrations.

28
The categories of this paper are: alg-geom
35
The categories of this paper are: mtrl-th
30
The categories of this paper are: q-alg
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The categories of this paper are: comp-gas
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The categories of this paper are: funct-an
5
The categories of this paper are: gr-qc
8
The categories of this paper are: hep-ex
16
The categories of this paper are: stat
31
The categories of this paper are: ao-sci
36
The categories of this paper are: cmp-lg
0
The categories of this paper are: hep-ph
23
The categories of this paper are: solv-int
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The categories of this paper are: dg-ga
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The categories of this paper are: acc-phys
15
The categories of this paper are: nucl-ex
18
The categories of this paper are: econ