Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A review of Lie 2-algebras   We first recall two equivalent definitions of Lie $2$-algebras,
categorification of Lie algebras and $2$-term $L_\infty$-algebras. Then we
present four different kinds of Lie $2$-algebras from $2$-plectic manifolds,
Courant algebroids, homotopy Poisson manifolds and affine multivector fields on
a Lie groupoid respectively. Moreover, we recall the cohomology theory of Lie
$2$-algebras and analyze its lower degree cases. The integration of strict Lie
$2$-algebras to strict Lie $2$-groups is also discussed.

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The categories of this paper are: hep-ph
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The categories of this paper are: plasm-ph
22
The categories of this paper are: chao-dyn
5
The categories of this paper are: gr-qc
3
The categories of this paper are: physics
27
The categories of this paper are: comp-gas
16
The categories of this paper are: stat
35
The categories of this paper are: mtrl-th
32
The categories of this paper are: atom-ph
37
The categories of this paper are: supr-con
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The categories of this paper are: q-bio
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The categories of this paper are: hep-lat
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The categories of this paper are: cs
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The categories of this paper are: nucl-ex
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The categories of this paper are: astro-ph
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The categories of this paper are: eess