Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Squeezed in three dimensions, moving in two: Hydrodynamic theory of 3D
  incompressible easy-plane polar active fluids   We study the hydrodynamic behavior of three dimensional (3D) incompressible
collections of self-propelled entities in contact with a momentum sink in a
state with non-zero average velocity, hereafter called 3D easy-plane
incompressible polar active fluids. We show that the hydrodynamic model for
this system belongs to the same universality class as that of an equilibrium
system, namely a special 3D anisotropic magnet. The latter can be further
mapped onto yet another equilibrium system, a DNA-lipid mixture in the sliding
columnar phase. Through these connections we find a divergent renormalization
of the damping coefficients in 3D easy-plane incompressible polar active
fluids, and obtain their equal-time velocity correlation functions.

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The categories of this paper are: cs
25
The categories of this paper are: patt-sol
11
The categories of this paper are: hep-lat
33
The categories of this paper are: plasm-ph
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The categories of this paper are: acc-phys
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The categories of this paper are: quant-ph
5
The categories of this paper are: gr-qc
17
The categories of this paper are: q-fin
15
The categories of this paper are: nucl-ex
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The categories of this paper are: supr-con
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The categories of this paper are: stat
30
The categories of this paper are: q-alg
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The categories of this paper are: astro-ph
0
The categories of this paper are: hep-ph
29
The categories of this paper are: funct-an
26
The categories of this paper are: bayes-an