Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Two-point function reduction of four-point amputated functions and
  transformations in $F\bar{F}$ and RA basis in a real-time finite temperature
  NJL model   Based on a general analysis of Green functions in the real-time thermal field
theory, we have proven that the four-point amputated functions in a NJL model
in the fermion bubble diagram approximation behave like usual two-point
functions. We expound the thermal transformations of the matrix propagator for
a scalar bound state in the $F\bar{F}$ basis and in the $RA$ basis. The
resulting physical causal, advanced and retarded propagator are respectively
identical to corresponding ones derived in the imaginary-time formalism and
this shows once again complete equivalence of the two formalisms of thermal
field theory on the discussed problem in the NJL model.

5
The categories of this paper are: gr-qc
14
The categories of this paper are: math-ph
3
The categories of this paper are: physics
27
The categories of this paper are: comp-gas
28
The categories of this paper are: alg-geom
8
The categories of this paper are: hep-ex
6
The categories of this paper are: astro-ph
1
The categories of this paper are: cs
19
The categories of this paper are: eess
20
The categories of this paper are: acc-phys
29
The categories of this paper are: funct-an
13
The categories of this paper are: quant-ph
24
The categories of this paper are: dg-ga
32
The categories of this paper are: atom-ph
34
The categories of this paper are: chem-ph
30
The categories of this paper are: q-alg