Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Classification of Subsystems for Local Nets with Trivial Superselection
  Structure   Let F be a local net of von Neumann algebras in four spacetime dimensions
satisfying certain natural structural assumptions. We prove that if F has
trivial superselection structure then every covariant, Haag-dual subsystem B is
the fixed point net under a compact group action on one component in a suitable
tensor product decomposition of F. Then we discuss some application of our
result, including free field models and certain theories with at most countably
many sectors.

13
The categories of this paper are: quant-ph
35
The categories of this paper are: mtrl-th
15
The categories of this paper are: nucl-ex
23
The categories of this paper are: solv-int
27
The categories of this paper are: comp-gas
17
The categories of this paper are: q-fin
25
The categories of this paper are: patt-sol
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The categories of this paper are: eess
0
The categories of this paper are: hep-ph
9
The categories of this paper are: nlin
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The categories of this paper are: cmp-lg
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The categories of this paper are: atom-ph
7
The categories of this paper are: hep-th
18
The categories of this paper are: econ
8
The categories of this paper are: hep-ex
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The categories of this paper are: hep-lat