Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A remark about unitary representations of Lorentz group and an equation
  for zero mass particles   In the present note the expansion of the wave function of a massless particle
(with the definite value of its helicity) over the untary irreducible
representaions of the Lorentz group (defined on the light cone) is used as for
the analog of the Fourier transformation for deriving of an equation in the
relativistic configuration representation.

6
The categories of this paper are: astro-ph
9
The categories of this paper are: nlin
15
The categories of this paper are: nucl-ex
13
The categories of this paper are: quant-ph
30
The categories of this paper are: q-alg
16
The categories of this paper are: stat
3
The categories of this paper are: physics
29
The categories of this paper are: funct-an
0
The categories of this paper are: hep-ph
33
The categories of this paper are: plasm-ph
24
The categories of this paper are: dg-ga
5
The categories of this paper are: gr-qc
25
The categories of this paper are: patt-sol
17
The categories of this paper are: q-fin
12
The categories of this paper are: nucl-th
4
The categories of this paper are: cond-mat