Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Metal-insulator transition in the Hubbard model: a simple description
  including the Kondo effect   The electron spectrum structure in the half-filled Hubbard model is
considered in terms of the one-particle Green's functions within many-electron
representation. A simple analytical generalization of the single-site
Hubbard-III approximation is obtained, which takes into account the Fermi
excitations (Kondo terms). The problem of the metal-insulator transition is
investigated. The occurrence of a three-peak density-of-states structure
including the "Kondo" peak at the Fermi level is discussed. A comparison with
large-d calculations is performed.

29
The categories of this paper are: funct-an
17
The categories of this paper are: q-fin
10
The categories of this paper are: q-bio
37
The categories of this paper are: supr-con
26
The categories of this paper are: bayes-an
20
The categories of this paper are: acc-phys
35
The categories of this paper are: mtrl-th
30
The categories of this paper are: q-alg
8
The categories of this paper are: hep-ex
23
The categories of this paper are: solv-int
18
The categories of this paper are: econ
21
The categories of this paper are: adap-org
14
The categories of this paper are: math-ph
24
The categories of this paper are: dg-ga
15
The categories of this paper are: nucl-ex
16
The categories of this paper are: stat