Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Irreducible tensor form of three-particle operator for open-shell atoms   The three-particle operator in a second quantized form is studied. The
operator is transformed into irreducible tensor form. Possible coupling
schemes, distinguished by the classes of symmetric group \mathrm{S_{6}}, are
presented. Recoupling coefficients, which allow one to transform given scheme
into another, are produced by using the angular momentum theory, combined with
quasispin formalism. The classification of three-particle operator, which acts
on n=1,2,...,6 open shells of equivalent electrons of atom, is considered. The
procedure to construct three-particle matrix elements are examined.

17
The categories of this paper are: q-fin
34
The categories of this paper are: chem-ph
37
The categories of this paper are: supr-con
13
The categories of this paper are: quant-ph
36
The categories of this paper are: cmp-lg
25
The categories of this paper are: patt-sol
0
The categories of this paper are: hep-ph
14
The categories of this paper are: math-ph
24
The categories of this paper are: dg-ga
19
The categories of this paper are: eess
32
The categories of this paper are: atom-ph
6
The categories of this paper are: astro-ph
15
The categories of this paper are: nucl-ex
11
The categories of this paper are: hep-lat
28
The categories of this paper are: alg-geom
35
The categories of this paper are: mtrl-th