Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Almost Kahler 4-manifolds with J-invariant Ricci tensor and special Weyl
  tensor   We study the question of integrability of a compatible almost complex
structure on a compact symplectic 4-manifold, under various natural assumptions
on the curvature of the associated almost Kahler metric.

21
The categories of this paper are: adap-org
33
The categories of this paper are: plasm-ph
7
The categories of this paper are: hep-th
1
The categories of this paper are: cs
23
The categories of this paper are: solv-int
8
The categories of this paper are: hep-ex
11
The categories of this paper are: hep-lat
19
The categories of this paper are: eess
18
The categories of this paper are: econ
28
The categories of this paper are: alg-geom
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The categories of this paper are: mtrl-th
31
The categories of this paper are: ao-sci
34
The categories of this paper are: chem-ph
20
The categories of this paper are: acc-phys
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The categories of this paper are: comp-gas
36
The categories of this paper are: cmp-lg