Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Massive fermions in 2+1 dimensions   We construct the higher-spin massive fermionic fields in 2+1 dimensions.
Their field equations and propagators are derived from first principle. For
fields with j>1/2, complications arise from the non-linear behaviour of the
boost operators. We find that for a spin-three-half field, the non-linearity
have an underlying structure that guarantees the locality of the fields and the
existence of covariant propagators. We conjecture that this structure exists
for fields of all spin.

10
The categories of this paper are: q-bio
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The categories of this paper are: physics
22
The categories of this paper are: chao-dyn
9
The categories of this paper are: nlin
8
The categories of this paper are: hep-ex
29
The categories of this paper are: funct-an
33
The categories of this paper are: plasm-ph
37
The categories of this paper are: supr-con
34
The categories of this paper are: chem-ph
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The categories of this paper are: q-fin
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The categories of this paper are: solv-int
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The categories of this paper are: bayes-an
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The categories of this paper are: acc-phys
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The categories of this paper are: nucl-th
31
The categories of this paper are: ao-sci
0
The categories of this paper are: hep-ph