Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Review of AdS/CFT Integrability, Chapter IV.4: Integrability in QCD and
  N<4 SYM   There is a growing amount of evidence that QCD (and four-dimensional gauge
theories in general) possess a hidden symmetry which does not exhibit itself as
a symmetry of classical Lagrangians but is only revealed on the quantum level.
In this review we consider the scale dependence of local gauge invariant
operators and high-energy (Regge) behavior of scattering amplitudes to explain
that the effective QCD dynamics in both cases is described by completely
integrable systems that prove to be related to the celebrated Heisenberg spin
chain and its generalizations.

1
The categories of this paper are: cs
17
The categories of this paper are: q-fin
10
The categories of this paper are: q-bio
13
The categories of this paper are: quant-ph
20
The categories of this paper are: acc-phys
2
The categories of this paper are: math
22
The categories of this paper are: chao-dyn
37
The categories of this paper are: supr-con
21
The categories of this paper are: adap-org
14
The categories of this paper are: math-ph
23
The categories of this paper are: solv-int
18
The categories of this paper are: econ
3
The categories of this paper are: physics
30
The categories of this paper are: q-alg
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The categories of this paper are: nucl-ex
26
The categories of this paper are: bayes-an