Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On the ground state and excitations of a four-component fermion model   The properties of the ground state and excitations of a four-component
Hubbard-like model are studied by the Lieb-Schultz-Mattis approach. It is
proven rigorously that the ground state of the model is nondegenerate and
excitations are gapless at all band fillings.

2
The categories of this paper are: math
17
The categories of this paper are: q-fin
25
The categories of this paper are: patt-sol
33
The categories of this paper are: plasm-ph
28
The categories of this paper are: alg-geom
0
The categories of this paper are: hep-ph
22
The categories of this paper are: chao-dyn
14
The categories of this paper are: math-ph
9
The categories of this paper are: nlin
35
The categories of this paper are: mtrl-th
11
The categories of this paper are: hep-lat
26
The categories of this paper are: bayes-an
18
The categories of this paper are: econ
8
The categories of this paper are: hep-ex
23
The categories of this paper are: solv-int
10
The categories of this paper are: q-bio