Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Approximate spectral functions in thermal field theory   Causality requires, that the (anti-) commutator of two interacting field
operators vanishes for space-like coordinate differences. This implies, that
the Fourier transform of the spectral function of this quantum field should
vanish in the space-like domain. We find, that this requirement imposes some
constraints on the use of resummed propagators in high temperature gauge
theory.

5
The categories of this paper are: gr-qc
33
The categories of this paper are: plasm-ph
22
The categories of this paper are: chao-dyn
18
The categories of this paper are: econ
26
The categories of this paper are: bayes-an
27
The categories of this paper are: comp-gas
34
The categories of this paper are: chem-ph
4
The categories of this paper are: cond-mat
20
The categories of this paper are: acc-phys
35
The categories of this paper are: mtrl-th
37
The categories of this paper are: supr-con
16
The categories of this paper are: stat
19
The categories of this paper are: eess
23
The categories of this paper are: solv-int
24
The categories of this paper are: dg-ga
3
The categories of this paper are: physics