Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Dyson-Schwinger equations and their application to nonperturbative field
  theory   Two examples of recent progress in applications of the Dyson-Schwinger
equation (DSE) formalism are presented: (1) Strong coupling quantum
electrodynamics in 4 dimensions (QED$_4$) is an often studied model, which is
of interest both in its own right and as an abelian model of quantum
chromodynamics (QCD). We present results from a study of subtractive
renormalization of the fermion propagator Dyson-Schwinger equation (DSE) in
massive strong-coupling quenched QED$_4$. The procedure is straightforward to
implement and numerically stable. (2) The Bethe-Salpeter equation (BSE) with a
class of non-ladder scattering kernels is solved in {\it Minkowski space} in
terms of the perturbation theory integral representation (PTIR). We consider a
bound state of two spinless particles with the formal expression of the full
scattering kernel in a $\phi^2\sigma$ scalar model. We derive an integral
equation for the weight function with a real kernel. We recover as a check
results for the massive scalar ladder approximation.

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The categories of this paper are: ao-sci
10
The categories of this paper are: q-bio
11
The categories of this paper are: hep-lat
30
The categories of this paper are: q-alg
32
The categories of this paper are: atom-ph
3
The categories of this paper are: physics
15
The categories of this paper are: nucl-ex
27
The categories of this paper are: comp-gas
33
The categories of this paper are: plasm-ph
6
The categories of this paper are: astro-ph
5
The categories of this paper are: gr-qc
19
The categories of this paper are: eess
14
The categories of this paper are: math-ph
34
The categories of this paper are: chem-ph
12
The categories of this paper are: nucl-th
28
The categories of this paper are: alg-geom