Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Superselection in the presence of constraints   For systems which contain both superselection structure and constraints, we
study compatibility between constraining and superselection. Specifically, we
start with a generalisation of Doplicher-Roberts superselection theory to the
case of nontrivial centre, and a set of Dirac quantum constraints and find
conditions under which the superselection structures will survive constraining
in some form. This involves an analysis of the restriction and factorisation of
superselection structures. We develop an example for this theory, modelled on
interacting QED.

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The categories of this paper are: q-bio
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The categories of this paper are: bayes-an
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The categories of this paper are: astro-ph
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The categories of this paper are: nucl-th
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The categories of this paper are: stat
22
The categories of this paper are: chao-dyn
28
The categories of this paper are: alg-geom
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The categories of this paper are: patt-sol
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The categories of this paper are: funct-an
30
The categories of this paper are: q-alg
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The categories of this paper are: cmp-lg
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The categories of this paper are: comp-gas
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The categories of this paper are: hep-lat
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The categories of this paper are: cond-mat
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The categories of this paper are: gr-qc
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The categories of this paper are: physics