Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Some mathematics for quasi-symmetry   Quasi-symmetry of a steady magnetic field means integrability of first-order
guiding-centre motion. Here we derive many restrictions on the possibilities
for a quasi-symmetry. We also derive an analogue of the Grad-Shafranov equation
for the flux function in a quasi-symmetric magnetohydrostatic field.

1
The categories of this paper are: cs
25
The categories of this paper are: patt-sol
19
The categories of this paper are: eess
31
The categories of this paper are: ao-sci
9
The categories of this paper are: nlin
11
The categories of this paper are: hep-lat
16
The categories of this paper are: stat
30
The categories of this paper are: q-alg
3
The categories of this paper are: physics
6
The categories of this paper are: astro-ph
37
The categories of this paper are: supr-con
24
The categories of this paper are: dg-ga
33
The categories of this paper are: plasm-ph
10
The categories of this paper are: q-bio
21
The categories of this paper are: adap-org
26
The categories of this paper are: bayes-an