Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Group-theoretic relations for amplitudes in gauge theories with
  orthogonal and symplectic groups   It is important to find nontrivial constraint relations for color-ordered
amplitudes in gauge theories. In the past several years, a pure group-theoretic
iterative method has been proposed to derive linear constraints on
color-ordered amplitudes in SU(N) gauge theories. In this paper, we use the
same method to derive linear constraints on four-point gluon amplitudes in
SO(N) and Sp(2N) gauge theories. These constraints are derived up to four-loop
order. It is found that there are $n=1,6,10,13,16$ constraint relations at
$L=0,1,2,3,4$ loop orders in both SO(N) and Sp(2N) cases. Correspondingly, the
numbers of independent four-point color-ordered amplitudes are $2,3, 5, 8, 11$
at $L=0,1,2,3,4$ loop orders in both theories.

27
The categories of this paper are: comp-gas
30
The categories of this paper are: q-alg
0
The categories of this paper are: hep-ph
34
The categories of this paper are: chem-ph
4
The categories of this paper are: cond-mat
24
The categories of this paper are: dg-ga
23
The categories of this paper are: solv-int
29
The categories of this paper are: funct-an
5
The categories of this paper are: gr-qc
9
The categories of this paper are: nlin
36
The categories of this paper are: cmp-lg
11
The categories of this paper are: hep-lat
22
The categories of this paper are: chao-dyn
35
The categories of this paper are: mtrl-th
31
The categories of this paper are: ao-sci
32
The categories of this paper are: atom-ph