Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Surface defects in gauge theory and KZ equation   We study the regular surface defect in the Omega-deformed four-dimensional
supersymmetric gauge theory with gauge group SU(N) with 2N hypermultiplets in
fundamental representation. We prove its vacuum expectation value obeys the
Knizhnik-Zamolodchikov equation for the 4-point conformal block of current
algebra of a two-dimensional conformal field theory. The level and the vertex
operators are determined by the parameters of the Omega-background and the
masses of the hypermultiplets; the cross-ratio of the 4 points is determined by
the complexified gauge coupling. We clarify that in a somewhat subtle way the
branching rule is parametrized by the Coulomb moduli. This is an example of the
BPS/CFT relation.

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The categories of this paper are: supr-con
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The categories of this paper are: q-fin
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The categories of this paper are: acc-phys
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The categories of this paper are: cmp-lg
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The categories of this paper are: cond-mat
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The categories of this paper are: adap-org
5
The categories of this paper are: gr-qc
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The categories of this paper are: plasm-ph
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The categories of this paper are: patt-sol
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The categories of this paper are: atom-ph
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The categories of this paper are: q-alg
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The categories of this paper are: alg-geom
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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: hep-lat
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The categories of this paper are: nlin