Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The neutrino propagator in matter and its spin properties   A spectral representation for the neutrino propagator in a moving matter with
constant density is constructed. It is found that in a matter there exists a
4-dimensional axis of complete polarization, all poles of the propagator are
classified according to the values of the spin projection onto this axis.

32
The categories of this paper are: atom-ph
21
The categories of this paper are: adap-org
3
The categories of this paper are: physics
18
The categories of this paper are: econ
30
The categories of this paper are: q-alg
37
The categories of this paper are: supr-con
9
The categories of this paper are: nlin
24
The categories of this paper are: dg-ga
17
The categories of this paper are: q-fin
25
The categories of this paper are: patt-sol
20
The categories of this paper are: acc-phys
4
The categories of this paper are: cond-mat
10
The categories of this paper are: q-bio
19
The categories of this paper are: eess
28
The categories of this paper are: alg-geom
5
The categories of this paper are: gr-qc