Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On the possibility to use non-orthogonal orbitals for Density Matrix
  Renormalization Group calculations in Quantum Chemistry   The generalization of Density Matrix Renormalization Group (DMRG) approach as
implemented in quantum chemistry, to the case of non-orthogonal orbitals is
carefully analyzed. This generalization is attractive from the physical point
of view since it allows a better localization of the orbitals. The possible
implementation difficulties and drawbacks are estimated. General formulae for
hamiltonian matrix elements useful in DMRG calculations are given.

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The categories of this paper are: nlin
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The categories of this paper are: patt-sol
20
The categories of this paper are: acc-phys
16
The categories of this paper are: stat
12
The categories of this paper are: nucl-th
37
The categories of this paper are: supr-con
24
The categories of this paper are: dg-ga
2
The categories of this paper are: math
34
The categories of this paper are: chem-ph
1
The categories of this paper are: cs
33
The categories of this paper are: plasm-ph
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The categories of this paper are: funct-an
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The categories of this paper are: q-alg
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The categories of this paper are: astro-ph
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The categories of this paper are: hep-ex
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The categories of this paper are: quant-ph