Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Hamel's Formalism and Variational Integrators on a Sphere   This paper discusses Hamel's formalism and its applications to
structure-preserving integration of mechanical systems. It utilizes redundant
coordinates in order to eliminate multiple charts on the configuration space as
well as nonphysical artificial singularities induced by local coordinates,
while keeping the minimal possible degree of redundancy and avoiding
integration of differential-algebraic equations.

1
The categories of this paper are: cs
11
The categories of this paper are: hep-lat
7
The categories of this paper are: hep-th
27
The categories of this paper are: comp-gas
17
The categories of this paper are: q-fin
30
The categories of this paper are: q-alg
21
The categories of this paper are: adap-org
19
The categories of this paper are: eess
24
The categories of this paper are: dg-ga
8
The categories of this paper are: hep-ex
10
The categories of this paper are: q-bio
6
The categories of this paper are: astro-ph
31
The categories of this paper are: ao-sci
18
The categories of this paper are: econ
32
The categories of this paper are: atom-ph
16
The categories of this paper are: stat