Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Electronic properties and Fermi surfaces MgCNi$_{3}$ and related
  intermetallics   The band structure of the new perovskite-like superconductor MgCNi$_{3}$ was
studied by the self-consistent FP-LMTO method. The superconducting properties
of MgCNi$_{3}$ are associated with an intensive peak in the density of Ni3d
states near the Fermi level. The absence of superconductivity for
nonstoichiometric compositions MgC$_{1-x}$Ni$_{3}$ is due to the transition of
the system to the magnetic state. The possibility of superconductivity was
discussed for intermetallics ScBNi$_{3}$, InBNi$_{3}$, MgCCo$_{3}$ and
MgCCu$_{3}$ which are isostructural with MgCNi$_{3}$.

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The categories of this paper are: physics
28
The categories of this paper are: alg-geom
16
The categories of this paper are: stat
12
The categories of this paper are: nucl-th
19
The categories of this paper are: eess
13
The categories of this paper are: quant-ph
6
The categories of this paper are: astro-ph
37
The categories of this paper are: supr-con
30
The categories of this paper are: q-alg
25
The categories of this paper are: patt-sol
20
The categories of this paper are: acc-phys
32
The categories of this paper are: atom-ph
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The categories of this paper are: hep-th
18
The categories of this paper are: econ
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The categories of this paper are: gr-qc
31
The categories of this paper are: ao-sci