Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Homotopic Classification of Yang-Mills Vacua Taking into Account
  Causality   Existence of theta-vacuum states in Yang--Mills theories defined over
asymptotically flat space-times examined taking into account not only the
topology but the complicated causal structure of these space-times, too. By a
result of Galloway apparently causality makes all vacuum states, seen by a
distant observer, homotopically equivalent making the introduction of
theta-terms unnecessary. But a more careful analysis shows that certain twisted
classical vacuum states survive even in this case eventually leading to the
conclusion that the concept of ``theta-vacua'' is meaningful in the case of
general Yang--Mills theories. We give a classification of these vacuum states
based on Isham's results showing that the Yang--Mills vacuum has the same
complexity as in the flat Minkowskian case hence the general CP-problem is not
more complicated than the well-known flat one. We also construct the theta
vacua rigorously via geometric quantization.

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The categories of this paper are: hep-ex
36
The categories of this paper are: cmp-lg
37
The categories of this paper are: supr-con
19
The categories of this paper are: eess
29
The categories of this paper are: funct-an
17
The categories of this paper are: q-fin
14
The categories of this paper are: math-ph
27
The categories of this paper are: comp-gas
32
The categories of this paper are: atom-ph
0
The categories of this paper are: hep-ph
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The categories of this paper are: nlin
12
The categories of this paper are: nucl-th
16
The categories of this paper are: stat
25
The categories of this paper are: patt-sol
22
The categories of this paper are: chao-dyn
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The categories of this paper are: ao-sci