Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Revisiting Wess-Zumino-Witten terms   We revisit various topological issues concerning four-dimensional ungauged
and gauged Wess-Zumino-Witten (WZW) terms for $SU$ and $SO$ quantum
chromodynamics (QCD), from the modern bordism point of view. We explain, for
example, why the definition of the $4d$ WZW terms requires the spin structure.
We also discuss how the mixed anomaly involving the 1-form symmetry of $SO$ QCD
is reproduced in the low-energy sigma model.

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The categories of this paper are: supr-con
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The categories of this paper are: atom-ph
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The categories of this paper are: eess
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The categories of this paper are: cmp-lg
2
The categories of this paper are: math
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The categories of this paper are: mtrl-th
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The categories of this paper are: physics
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The categories of this paper are: q-fin
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The categories of this paper are: math-ph
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The categories of this paper are: hep-ex
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The categories of this paper are: stat
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The categories of this paper are: econ
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The categories of this paper are: dg-ga
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The categories of this paper are: plasm-ph
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The categories of this paper are: nucl-ex
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The categories of this paper are: alg-geom