Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Introduction to Chiral Symmetry   These lectures are an attempt to a pedagogical introduction into the
elementary concepts of chiral symmetry in nuclear physics. Effective chiral
models such as the linear and nonlinear sigma model will be discussed as well
as the essential ideas of chiral perturbation theory. Some applications to the
physics of ultrarelativistic heavy ion collisions will be presented.

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The categories of this paper are: astro-ph
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The categories of this paper are: cmp-lg
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The categories of this paper are: q-bio
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The categories of this paper are: nlin
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The categories of this paper are: econ
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The categories of this paper are: hep-ex
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The categories of this paper are: math-ph
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The categories of this paper are: acc-phys
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The categories of this paper are: gr-qc
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The categories of this paper are: quant-ph
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The categories of this paper are: mtrl-th
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The categories of this paper are: dg-ga
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The categories of this paper are: hep-ph
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The categories of this paper are: math
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The categories of this paper are: funct-an
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The categories of this paper are: hep-lat